The precise ways the game breaks down at higher levels /u/Tornagh DnD: Roll for Initiative!

I see many posts about the game being most commonly played at lower levels, with typical campaigns starting somewhere between levels 1 and 3, and usually ending in the level 8 to 12 range.

I however don’t see many posts explaining why. When this question comes up I see generalized answers that broadly speaking say “the party is too powerful and versatile”, which is partly true, but also partly false. There are in fact many ways in which a level 15 party facing typical enemies of that level is far weaker than a level 7 party facing typical enemies at their level, and some of these aspects of the game feel somewhat broken and not particularly fun to me.

Having DM’ed a 5e game all the way from level 3 to 20, I thought I will document my findings here for the community.

Summary:

1. It is true that spell casters get many options that allow them to circumvent most encounters. This is doubly true once Wish is unlocked, as Wish can be used to replicate any other spell that is level 8 or lower. Personally I did not see this as a problem as a DM, but some stories can suffer from this as the party can reasonably easily solve 95% of problems instantly with the right spell.
2. The effectiveness of Player AC drops off linearly as the party levels and most characters actually become a lot squishier than they were at mid levels. This is due to AC not really scaling with levels while enemy hit chance keeps scaling. It is trivial to build a character that is only getting hit on a crit at level 5, the same exact character is going to be getting hit a lot when facing high CR creatures. To give you an example on the lower end of the AC scaling spectrum, a level 1 wizard has the same exact amount of AC as a level 20 wizard (unless the latter gets specific magic items to help with this), while the typical enemy goes from having a +4 to hit to +14 inbetween CR1 and CR20 (and this keeps scaling above CR20). To give another example on the higher end of the AC spectrum, a multiclassed paladin with shield of faith, plate armor, a physical shield and the shield spell will get 26 AC without magical items. They can get this as soon as level 2. They usually max out at 32 AC and ALL of the 6 AC difference comes in the form of +3 magic items, which in my experience most parties can access already at tier 2 or 3 of play. In both cases enemies hit chance scales faster than the party’s AC, leading to a strange bell curve of starting out squishy due to low HP at low levels, becoming unkillable juggernauts at mid levels due to getting amazing AC and decent HP, then ending up squishy again at high levels due to AC being outscaled by hitchance.
3. Player’s chance to save without proficiency against enemy spells and effects drops linearly from a reasonable 50%-ish chance to 0% chance. This is a much bigger deal than you may assume at first. There are creatures where not saving against their effect can stun the whole party. A stunned party can very quickly turns into a dead party. This makes the resilient feat super important. To give you a concrete example of the scaling issue, a sorcerer starting with 10 wisdom will have 1d20+0 to wisdom saves at level 1, and the same 1d20+0 to wisdom saves at level 20. At the same time enemy spells and effects will go from reasonably low dc’s like 12 at CR1 to DC 21+ at CR20 and above. So in this example the Sorcerer goes from having a 50% chance to save vs wisdom targeting effects and spells to 0% chance to save against the same kind of effects. Save effectiveness drops linearly, so the party can already suffer from this at medium levels and it only gets worse from there (unless the party heavily invests into resilient feats).
4. As per points 2 and 3, the party’s passive inherent defenses get a lot weaker at higher levels, however this can be counteracted by clever uses of spells like clone, contingency and simulacrums as per point 1. This become even more true once Wish is unlocked as that spell allows the party to set up their defenses without spending money on expensive components. These options however are only available to spell-casters, so the sword and board martial is just going to go from an impossible to hit juggernaut at level 5 to someone constantly taking HP damage and often yoyo-ing up and down at the cadence of attacks and healing words at level 20.
5. The effectiveness of AOE damage spells spikes up at level 5 then drops off in a linear way as the party levels. A Fireball or two cast into a horde of enemies at level 5 is likely to outright kill many of them. an AOE damage spell at level 15 is very unlikely to do that. At levels 17+ Meteor swarm puts this option back on the menu, but Wish is usually a better level 9 spell to use. AOE spells thus technically follow a U shaped power curve, but the only good high level options are level 9 and you only ever get a single level 9 spellslot which is almost always better used on some other spell.
6. The effectiveness of single target disables also starts out really strong and then suddenly drops off a cliff when bosses get legendary resistances. These spells start out as a save or suck for the boss. As the party gets to higher levels bosses get legendary resistances and suddenly save or suck spells are much weaker. They are only really good at that point if the party is making a concerted effort to draw out the legendary resistances of the boss, but it is often more efficient at that point to just focus those actions on maximizing damage. Non-bosses are very rarely worth a concentration slot to disable via single target spells when he same concentration could be used on a wall of force or reverse gravity.
7. The effectiveness of single target damage spells also falls off a lot. The only exceptions to this are combos where either magic missile or scorching ray/eldritch blast are combined with effects that enhance either the base damage roll (for synergy with magic missile) or each attack roll (for synergy with scorching ray/eldritch blast). In 5e this required multiclassing shenanigans and thus casters had to sacrifice quite a lot to get good single target damage. It also had a linear-ish power curve thus martials were still competitive (and arguable better when taking into account fighter turn 1 nova). *This actually changed in 5.5e where Wizards and Bards have become DPR kings at medium to high levels, able to dish out 600+ damage a turn due to how ridiculously broken upcast conjure minor elementals is when combined with scorching ray. This was not yet the case when we played and I do not believe it to be intended by WOTC and I really hope they fix that spell eventually.
8. The effectiveness of AOE disables tends to get stronger at higher levels vs hordes with high level options such as wall of force and reverse gravity being exceptionally good against hordes of enemies.
9. Generally higher level parties tend to have accumulated a lot of magical items by the time they get to that level giving them additional options beyond what spells offer. Many of these items have really powerful effects. In the mid game flying items tend to be the most impactful in my experience as they allow a clever party to choose the engagement range. There are also very powerful caster items that may or may not be available in the campaign and which might only become available at higher tiers of play. Nevertheless, none of these items are strong enough to fully counteract the defensive scaling issues mentioned above. At most they give the players a different dimension of options to avoid getting killed such as the ability to fly out of reach with a carpet of flying or the ability to go and take a free long rest and come back with rod of security.

Personally I wasn’t too bothered by issue number 1 and 9 above because my campaign was built around giving the players as much flexibility as possible. There was a BBEG, but the players were actually being manipulated by it in a way that they didn’t realise up until the very end, thus the players having more options really just helped the baddie rather than hinder their plans.

However, I was somewhat surprised by the other scaling quirks, particularly when my formerly unkillable party suddenly started struggling to stay up in combat due to issues 2 and 3.

I would be very happy to answer any questions you may have about DM-ing or playing at high levels.

Edit: I am a little surprised to have to write this but just to clarify: RP is great, that’s what my players did in the vast majority of their time. We sometimes had multiple sessions of pure rp (mixed with some exploration) between combat encounters. However 5e rules are 90%+ about combat and since the analysis above focuses on how the rules interact, it will inherently be skewed towards what the rules cover most: combat.

I see many posts about the game being most commonly played at lower levels, with typical campaigns starting somewhere between levels 1 and 3, and usually ending in the level 8 to 12 range.

I however don’t see many posts explaining why. When this question comes up I see generalized answers that broadly speaking say “the party is too powerful and versatile”, which is partly true, but also partly false. There are in fact many ways in which a level 15 party facing typical enemies of that level is far weaker than a level 7 party facing typical enemies at their level, and some of these aspects of the game feel somewhat broken and not particularly fun to me.

Having DM’ed a 5e game all the way from level 3 to 20, I thought I will document my findings here for the community.

Summary:

1. It is true that spell casters get many options that allow them to circumvent most encounters. This is doubly true once Wish is unlocked, as Wish can be used to replicate any other spell that is level 8 or lower. Personally I did not see this as a problem as a DM, but some stories can suffer from this as the party can reasonably easily solve 95% of problems instantly with the right spell.
2. The effectiveness of Player AC drops off linearly as the party levels and most characters actually become a lot squishier than they were at mid levels. This is due to AC not really scaling with levels while enemy hit chance keeps scaling. It is trivial to build a character that is only getting hit on a crit at level 5, the same exact character is going to be getting hit a lot when facing high CR creatures. To give you an example on the lower end of the AC scaling spectrum, a level 1 wizard has the same exact amount of AC as a level 20 wizard (unless the latter gets specific magic items to help with this), while the typical enemy goes from having a +4 to hit to +14 inbetween CR1 and CR20 (and this keeps scaling above CR20). To give another example on the higher end of the AC spectrum, a multiclassed paladin with shield of faith, plate armor, a physical shield and the shield spell will get 26 AC without magical items. They can get this as soon as level 2. They usually max out at 32 AC and ALL of the 6 AC difference comes in the form of +3 magic items, which in my experience most parties can access already at tier 2 or 3 of play. In both cases enemies hit chance scales faster than the party’s AC, leading to a strange bell curve of starting out squishy due to low HP at low levels, becoming unkillable juggernauts at mid levels due to getting amazing AC and decent HP, then ending up squishy again at high levels due to AC being outscaled by hitchance.
3. Player’s chance to save without proficiency against enemy spells and effects drops linearly from a reasonable 50%-ish chance to 0% chance. This is a much bigger deal than you may assume at first. There are creatures where not saving against their effect can stun the whole party. A stunned party can very quickly turns into a dead party. This makes the resilient feat super important. To give you a concrete example of the scaling issue, a sorcerer starting with 10 wisdom will have 1d20+0 to wisdom saves at level 1, and the same 1d20+0 to wisdom saves at level 20. At the same time enemy spells and effects will go from reasonably low dc’s like 12 at CR1 to DC 21+ at CR20 and above. So in this example the Sorcerer goes from having a 50% chance to save vs wisdom targeting effects and spells to 0% chance to save against the same kind of effects. Save effectiveness drops linearly, so the party can already suffer from this at medium levels and it only gets worse from there (unless the party heavily invests into resilient feats).
4. As per points 2 and 3, the party’s passive inherent defenses get a lot weaker at higher levels, however this can be counteracted by clever uses of spells like clone, contingency and simulacrums as per point 1. This become even more true once Wish is unlocked as that spell allows the party to set up their defenses without spending money on expensive components. These options however are only available to spell-casters, so the sword and board martial is just going to go from an impossible to hit juggernaut at level 5 to someone constantly taking HP damage and often yoyo-ing up and down at the cadence of attacks and healing words at level 20.
5. The effectiveness of AOE damage spells spikes up at level 5 then drops off in a linear way as the party levels. A Fireball or two cast into a horde of enemies at level 5 is likely to outright kill many of them. an AOE damage spell at level 15 is very unlikely to do that. At levels 17+ Meteor swarm puts this option back on the menu, but Wish is usually a better level 9 spell to use. AOE spells thus technically follow a U shaped power curve, but the only good high level options are level 9 and you only ever get a single level 9 spellslot which is almost always better used on some other spell.
6. The effectiveness of single target disables also starts out really strong and then suddenly drops off a cliff when bosses get legendary resistances. These spells start out as a save or suck for the boss. As the party gets to higher levels bosses get legendary resistances and suddenly save or suck spells are much weaker. They are only really good at that point if the party is making a concerted effort to draw out the legendary resistances of the boss, but it is often more efficient at that point to just focus those actions on maximizing damage. Non-bosses are very rarely worth a concentration slot to disable via single target spells when he same concentration could be used on a wall of force or reverse gravity.
7. The effectiveness of single target damage spells also falls off a lot. The only exceptions to this are combos where either magic missile or scorching ray/eldritch blast are combined with effects that enhance either the base damage roll (for synergy with magic missile) or each attack roll (for synergy with scorching ray/eldritch blast). In 5e this required multiclassing shenanigans and thus casters had to sacrifice quite a lot to get good single target damage. It also had a linear-ish power curve thus martials were still competitive (and arguable better when taking into account fighter turn 1 nova). *This actually changed in 5.5e where Wizards and Bards have become DPR kings at medium to high levels, able to dish out 600+ damage a turn due to how ridiculously broken upcast conjure minor elementals is when combined with scorching ray. This was not yet the case when we played and I do not believe it to be intended by WOTC and I really hope they fix that spell eventually.
8. The effectiveness of AOE disables tends to get stronger at higher levels vs hordes with high level options such as wall of force and reverse gravity being exceptionally good against hordes of enemies.
9. Generally higher level parties tend to have accumulated a lot of magical items by the time they get to that level giving them additional options beyond what spells offer. Many of these items have really powerful effects. In the mid game flying items tend to be the most impactful in my experience as they allow a clever party to choose the engagement range. There are also very powerful caster items that may or may not be available in the campaign and which might only become available at higher tiers of play. Nevertheless, none of these items are strong enough to fully counteract the defensive scaling issues mentioned above. At most they give the players a different dimension of options to avoid getting killed such as the ability to fly out of reach with a carpet of flying or the ability to go and take a free long rest and come back with rod of security.

Personally I wasn’t too bothered by issue number 1 and 9 above because my campaign was built around giving the players as much flexibility as possible. There was a BBEG, but the players were actually being manipulated by it in a way that they didn’t realise up until the very end, thus the players having more options really just helped the baddie rather than hinder their plans.

However, I was somewhat surprised by the other scaling quirks, particularly when my formerly unkillable party suddenly started struggling to stay up in combat due to issues 2 and 3.

I would be very happy to answer any questions you may have about DM-ing or playing at high levels.

Edit: I am a little surprised to have to write this but just to clarify: RP is great, that’s what my players did in the vast majority of their time. We sometimes had multiple sessions of pure rp (mixed with some exploration) between combat encounters. However 5e rules are 90%+ about combat and since the analysis above focuses on how the rules interact, it will inherently be skewed towards what the rules cover most: combat.