It's no secret that the A.I. in BG:EE has been a sore point since release, but 1.2 fixed a lot of the issues. However, there are definitely still some kinks to iron out, and the same is true for BG2:EE.
For me the biggest issue is that none of the scripts work as well as the standard BG2 "Default" script. This was basically the same as "Standard attack" is now, except that you could rely on a character to actually do what you told them, and not worry about them suddenly charging of into battle.
It's especially annoying when playing a spellcaster. Sometimes you can instruct your character to cast a spell, but while waiting for the cooldown from the previous spell to expire, someone fires an arrow at you. This causes the spellcaster to disregard any previous order and engage the assailant with preferred weapon (previously he would also rush them despite being ranged).
This is also apparent with fighters. They tend to change targets when being attacked by multiple opponents. Even walking from A to B can be interrupted if an enemy appears.
I want a script that will allow an idle character to defend himself and party (just with weapon held), but not cause him to abort direct instructions from me. This is standard in vanilla BG1&2, and i want i back!
I haven't created a bug report as there are many already and surely this is among them, but with BG2:EE you have a lot more spellcasting to manage, and having my mages disregard my orders is becoming a real pain.
Oh, and disabling party A.I is really not a "solution" as I don't want micro every single encounter.