While I appreciate that the movie was trying to shift Tony from the self-centered narcissistic jerk superhero to the playfully self-centered narcissistic jerk superhero, it didn't really pan out as well as I hoped it would.
Much of Whiplash's behavior seemed borderline erratic. I mean, I simply don't buy the fact that his old man kicked off is a viable straw to break his back. Not to mention, he goes straight from drinking and brooding in the corner (admittedly, a very chilly corner) to a complete 180 where he's suddenly out to overtly destroy Stark's reputation, and even kill him toward the end.
Also, and I guess this is just me nit-picking now, but no sane person would do what he did. He builds an exoskeleton with what he has available, and picks a whip-like weapon. Alright, I'll buy that; it gives him range and unpredictability in attacks, yadda yadda... fine. When that fails to work (and it does fail), his solution is to build a big robot suit. Alright, not the most inventive tactic to counter a man-robot like Iron Man, but okay. Against Iron Man's repulsors and missiles (ignoring War Machine's weapons because he probably didn't plan on War Machine being converted mid-fight), what weapon does he go with? Whips. Again.
I'm sorry, but not even cartoon super-villains are that dimwitted. If a strategy doesn't work the first time, attaching it to a metal suit and making the extensions slightly more powerful isn't going to make it any more effective the second time; especially considering that Iron Man would now see the whips coming. There goes your element of surprise, Vlad.
Hammer was almost offensive to listen to at times. I get that he's supposed to amount to a "Tony Stark-esque" figure representing what Stark could have been like, but he just came off as a yippy little loudmouth with too much money. I mean, he barely qualifies as a villain, given that 90% of the movie is spent with his creations either killing their pilots or under the control of the crazy Russian.
In the end, as a nerd of varying interests, I am kind of glad I saw the flick. It was nice to see Sam Jackson do more with the Fury character than just leak spoilers after the credit roll, and I didn't mind Cheadle's Rhodey as much as I thought I would have (Howard was still a better fit, I think). I just wish I could have gotten more out of the experience than some teasers for the Avengers movie, some nifty one-liners from an underused Mickey Rourke, and a bar fight conducted in a pair of super-powered metal suits.