I'd like to see the AI using set piece attacks, for example casters standing about 50' behind a rank of warriors. If the warriors are defeated the casters fall back.. or if you try to flank the warriors, they fall back to intercept you and the casters fall back so they're 50' behind them..
Archers should move to flank front line attackers, thier arrows should harm their own side and possibly cause reprisals, like in diablo, if one mob hits another they fight it out...
Luring to ambush, a warrior runs out to you, attacks then retreats.. you follow and get ambushed..
Simple stuff... atm only seen in massively multiplayer online games.
Even basic stuff like npc teammates healing each other, giving support fire..