I'll leave Red Queen to handle the in-game side of the question, as she (please correct me if I'm mistaken) appears to have all the details marshalled and I don't at the moment... I'll just add on to the pen-and-paper side of the confusion. Again, this is said with the intention of helping to share information and clear up misunderstandings, not to argue or recriminate.
But barkskin is raising the base armor class to 16 . And nobarmor modifier can raise it only change the base ac to higher according niaras explanition.
Thats mean no haste no cover no shild of fate and no shild bonuses as well protection ring and cloak. Until you have less ac then 16.
[...]
But really guys its so stupid there is a situation the druid is full cover. Behind a wall and he is stuck with 16 ac the aganst all logic . This Sa- Compedium is bull...
Also if its suppose to curse you with 16 ac the all haste and shield of fate mirror image ligthing charges and the shove ring should not give +15 bonus ac to Barksin . Wat is clearly a bug.
So, just talking in terms of how it
Should work, if things are following 5e rules, you still sound like you're working with a little bit of a misunderstanding. I will try to be clearer.
Barkskin does not change your Base AC. You, as a character continue to use whatever the best method of AC calculation that you have available to you is to work out your AC. All Barkskin does is add the caveat that, if, after all working out, your AC would be lower than 16, then it is brought up to at least 16. It doesn't lock your AC at that number, or prevent it being raised.
So, here's another example of how it
Should work, if everything works correctly and follows 5e rules:
Imagine an NPC that you are escorting. She has 10 in all ability scores and is wearing leather armour. She has no class levels or perks, and so the best she can do for her AC is the 'standard' method, which in leather armour is - "11 + Dex mod", so her AC is 11. The Druid thinks that this is too low and risky, and so casts Barkskin on her. As her current AC is 11, this means that her actual final AC is now 16, in accordance with Barkskin.
During the escort mission, danger ensues, and the Cleric immediately casts shield of Faith on the NPC, without thinking about it. Here's what happens: The NPC is calculating her AC using the normal method, which in leather armour is "11 + Dex mod", and with Shield of Faith, adding +2 to that, her AC would now be 13 - that's
Still lower than 16, though, so her final Ac, if something were to attack her right now, would be
16.
As the danger heats up, the wizard tell the NPC to run and hide, and he casts Haste on her. So, now, The NPC is calculating her AC using the normal method, which in leather armour is "11 + Dex mod", and with Shield of Faith adding +2 to that and now Haste adding +2 to that, her AC would now be 15 - but that's
Still lower than 16, though, so her final Ac, if something were to attack her right now, would be
16.
The NPC runs, at very fast speed, over to a conveniently shaped rock barricade, which grants her three-quarters cover from the hostile enemies: Now, the NPC is calculating her AC using the normal method, which in leather armour is "11 + Dex mod". With Shield of Faith adding +2 to that, Haste adding +2 to that, and now three-quarters cover granting her a +5 to that, her AC, if something were to attack her, would be 20 (11(leather) + 2(SoF) +2(Haste) +5(three-quarters cover)! This is now higher than 16 - Barksin is still on her, and active, but the situation it cares about is not applicable, and it is no longer relevant to her AC calculation - her AC, if she is shot at, is
20. If she moves out from the cover, however, and is shot at in the open, Barkskin ensures that her AC is at least 16, not the 15 it would be without Barkskin.
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BG3 seems to be in a situation such that it allows you to rack up ridiculously high AC bonuses, almost like it was designed by people who don't really know D&d very well and just want to use its fame to pimp their brand... so if the fact that, in BG3, you can get some absurd +17 bonus to your existing AC (which might be as high as 17 on its own before those bonuses, leading to an AC over 30 at level 5) seems like a mistake or a silly outcome to you - it is, but there's a very good possibility that it's Larian's own decision-making and lack of understanding of the game that are at the root of it, not an inherent issue with the system.
