Just wanted to add something...it's not...entirely true...that the stock AI won't use any PRC abilities.
I made a Lich/Wizard and was taking it through HotR, and during the Hall of Mirrors clone fight, the AI apparently ran out of spells (Demlich, to be exact, so both of us were immune to non-epic spells), ran out of consumables, then proceeded to start to use the Lich "Alter Self"...repeatidly.
(Completely off topic, but as a tip, have epic spells at the ready if you do what I did, because otherwise you'll be stuck poking at yourself forever doing zero damage back and forth xD)