IM2 becomes a much better movie when you realize that Vanko and Hammer were never a threat. A healthy Tony wouldn't have had any problems with them. Vanko and Hammer was always a distraction.
The huge threat of the movie was actually Tony's personal issues. The way he was handling his possible death was screwing up his friendship with Rhodey, and his romance with Pepper. He needed to stop being a jerk and solve the problem that was plaguing him before becoming Iron Man and kicking ass once again.
Yes, it is still the weakest movie in the trilogy. But I'm not as harsh on it anymore now that I look at it like that.