Playing on authentic.
Granted, an AI should never be too strong. That being said, it also shouldn't act like it is doing obvious mistakes that even a newbie wouldn't do after some battles.
In particular, I am talking about enemies that use a ranged attack as their main weapon. Many many times, when these ranged enemies are engaged in melee, they actually shoot in melee, suffer the disadvantage, after which they THEN move away to also suffer an attack of opportunity.
It would make sense the other way around.
IF the AI wants to move out of melee, and has a ranged attack option that it wants to use, it should move out of melee and then use the ranged attack. No one would do it like the AI does. It makes no sense and it is probably something not too hard to fix.