Mine has always been defensive AI in general, which is kind of exacerbated by the lack of neutral zone pressure.
Since the AI can just skate in at will, it really highlights the AI's inability to pick up open players, or cover a play.
Too many times I get burned by two guys checking the same guy, defenders standing still and leaving backdoor plays open, and more importantly defenders chasing for physical checks as opposed to using their sticks once they're in close range.