D&D 5E Why no Proficiency bonus to AC?

[Remathilis]

This was the case for Star Wars Saga edition. Your defense was the better of Dex+Armor or Dex+Level or something like that. It made armor better to use at lower levels, but as you gained experience eventually you'd want to wear plain cloths. There were exceptions to this rule, like armor which enhanced certain attributes, but for the most part not really the norm. Case in point, Han Solo was such a high level that his Level bonus was higher than any armor he could wear.

Having played some various d20 Star Wars games in my day (Revised and Saga) that is the feel I was opting for. A system that lets you run around in suits and Victorian gowns and yet have some protection beyond straight Dex. Considering the time era and tone, I'd willing to try it, though I wouldn't do so in a traditional D&D game.

So Most PCs will have a starting AC of around 13 (8 + 2 + 3 Dex, with firearms being so important, Dex is going to be a god stat anyway. Embrace it). and maxing out at 19 (8 + 6 +5 Dex). Keeping in mind that a.) The concept is to use MM monsters mostly as-is, b.) magic items are extremely rare and c.) most PCs aren't going to have access to armor or shields, this seems like a good range of ACs (well within or even below bounded accuracy levels, where PCs routinely have 16 or greater ACs at level 1). Again, this all fits the genre and is to encourage PCs to go armorless, so it works for me.

 

[GrumpyGamer]

The idea behind the current system is that 100 orcs (insert other horde of low CR creatures) is scary to a 20th level character. If you take away bounded accuracy you can't use these creatures in higher level modules, as they won't hit short of a crit.

 

[Xeviat]

The idea behind the current system is that 100 orcs (insert other horde of low CR creatures) is scary to a 20th level character. If you take away bounded accuracy you can't use these creatures in higher level modules, as they won't hit short of a crit.

But 100 "acolytes" doesn't work the same, as their save DCs will be low to the Player save bonuses who have continued to scale above their AC.

Minion rules in 4E covered this. Mob rules in 3E covered it too. There are other ways. 5E chose "an X is an X, always", which does have its advantages in the simulationist department. It's interesting that other aspects of 5E went for a freeform, non simulationist direction.

 

[mpwylie]

And I get the not wanting a treadmil. But, at least when looking at the CR calculator table in the DMG, monster ACs continue to go up with levels. Without magic items, you're expecting about a 65% hit chance against an equal CR monster at most levels (the monster AC even goes up generally at the same levels that player stats and proficiencies go up).

Honestly I don't think the chart says what you think it says. That chart has 6 different factors and it more or less assigns a value for how challenging that variable is. So yes the ACs grow with CR on that chart but that just means that a monster with an AC of 20 is more of a challenge than a monster with a AC of 10. I don't see it correlating how you imply though when I look at the monsters in the book. I see CR 1/4th things with AC 17 and CR 17 things with AC 14. A CR23 Kraken has an AC of 18, a CR6 Drider has a 19. AC is one variable in the overall picture and CR does not = level, it equals the Challenge the mob is to kill.

So player AC is bounded sure, but really it's bounded for the monsters too. Generally the monsters in the book range from single digits to the mid20s, no higher than the ACs you can achieve with a character. I think things like this are what make 5E better than other editions, but to each his own. You can do whatever you want at your table, just have fun!

 

[MerricB]

But 100 "acolytes" doesn't work the same, as their save DCs will be low to the Player save bonuses who have continued to scale above their AC.

Have you somehow missed the bit where most PC saves *don't* scale?

Yes, a couple of PC saves do scale, so they have improved protection there, but it is, by design, not ALL of the saves.

 

[Xeviat]

Have you somehow missed the bit where most PC saves *don't* scale?

Yes, a couple of PC saves do scale, so they have improved protection there, but it is, by design, not ALL of the saves.

So as you gain more and more levels, you're supposed to become more susceptible to attacks?

 

[GrumpyGamer]

So as you gain more and more levels, you're supposed to become more susceptible to attacks?

As you gain more levels you generally have more HPs and can survive more attacks. So you can fight more enemies at a time, but only up to a certain point.

 

[Xeviat]

As you gain more levels you generally have more HPs and can survive more attacks. So you can fight more enemies at a time, but only up to a certain point.

If you're saying that Save DCs are involved in that too, a lot of those don't cause damage and are just as bad at 1st as they are later.

 

[MerricB]

If you're saying that Save DCs are involved in that too, a lot of those don't cause damage and are just as bad at 1st as they are later.

Both saves and AC are mostly flat at higher levels; the main way of dealing with bad magic is good magic - items or spells.

 

[Lehrbuch]

So as you gain more and more levels, you're supposed to become more susceptible to attacks?

No, as PC saves don't get worse as they advance in level.