Loved the movie, gave it top marks...
One, Scarlett Johansson so should get her own spin off movie. She showed in this movie that she has the skills to pull off action sequences, which was the biggest "up in the air" about her when her casting was announced. I think that putting her in the lead of her own film based around this character could, as was mentioned earlier in this thread, really break open the female superhero market.
two, I was happy that they made a point of showing, if not talking, about Tony's drinking issues. From Pepper's asking him if he was, to showing him with drinks in most every non iron man sequence, getting progressively heaver as his condition worsened. Tony was collapsing into himself and his personal demons were getting hold of him. I think that his big turn around moment was after watching his fathers message to him. A lot of his issues stemmed from his father and his precised relationship with him. That was the turning point when he was at his personal lowest, and what swung him around.
Three, Truncated timing with the final conflicts. This is a major problem of action films of late in general, and I was hoping that IM2 would be spared from it. Alas, my hopes didn't pan out, and my fears were true. That end battle was about 20 to 30 min's too short. It was cut too fast, and far to fast paced. This is a serious problem that hollywood needs to get under control!