According to me the real question is "If the dices have been changed twice because players missing attacks might be anti-fun, then why isn't the ennemy's AC reduced?" That's the only goal of ennemie's AC. Lower AC wouldn't have any consequences except that we'll miss less often. They have to know what they want : if missing is the main problem then they could just reduce the AC... Problem solved. Am I wrong ? Is there something I'm not thinking about related to AC ?
Lower AC does have another, major consequence: Lowering AC makes it easier to hit enemies with things which target their AC, but it does not affect things which require enemies to make saving throws to avoid or reduce the damage. The major consequence is that this devalues saving-throw attacks, and makes AC attacks more attractive. This upsets the balance between AC and Saving Throws.
If I'm not wrong doesn't giving easy advantage reinforce the problem even more than reducing the AC by (let's say) 1 or 2 points ? On the other hand I noticed that they increased the dexterity of many creatures in the game compared to the MM, which probably increase the issue you raised.
Serious question : In the PnP, aren't the spells that targets AC used less often at higher level when characters have higher level and more powerfull spells that require a ST ? It's something Saito brought in another thread and I found interresting to think about (as the non PnP player I am).
Originally Posted by Dragonsnooz
The truest response to this is that changing enemy AC is a lever to control on how difficult the DM wants the encounter to be. High ground advantage and low ground disadvantage affect both the player and enemies adding a chaotic factor (or distortionary, variable factor) to combat design. Resulting in lop-sided combat outcomes. (with no change to aggregate difficulty).
When we're talking about AC we are talking about survivability so in conjunction with HP we can deduce a statistic of "turns-to-kill". High ground advantage reduces turns-to-kill and low ground disadvantage increases turns-to-kill.
AC adjustments are a good thing for DMs to consider as they are static, and there are spells to counter high AC enemies (crowd control or saving-throw damage). It's something the player can react to on the fly. Lowering AC can bring in normally tougher enemies to make the situation more immersive or exciting. Or, as brought up before with analyzing goblin stats, you can make a more consistent turn-to-kill by lowering AC and increasing HP.
Verticality is different, a player will enter a fight and see enemies on high ground and their characters on the low ground and rationalize "forget this, I'll reload and reposition". Or maybe, "Yeah I'll spend several turns focused on moving my characters around and chugging potions". Neither of which are engaging decisions. Again this did not impact difficulty but directly affects how the player spends their time. (The mechanic is essentially a chore for the player, just as exciting as washing dishes).
Thx for this. It gaves me more things to think about. What else could I do than "thinking" about BG3 I was exactly thinking about HP bloat that should be "necessary" if you reduced the AC. But I guess it's not the only solution because it also has (I think I can say "small") consequences.