Tony Stark seems to be much more laid back in Iron Man 3, especially compared to Pepper Potts. Pepper is way more action than Tony, especially at the end. Tony makes jokes, which one could argue makes him awesome, but Pepper totally destroys the villain(s) in Iron Man 3, which was way more awesome than a few puns here and there.
Iron Man 1, Tony is dying, and Pepper kills the lead villain without even getting into armor herself.
Iron Man 2, the lead villain ceases to be interesting and then is defeated by Tony.
Iron Man 3, Pepper again kills the lead villain, this time with a tank missile! (still curious why Tony did not think of trying that against the Iron Man 1 villain)