That's a valid complaint but generally speaking the Iron Man movies (and even Iron Man as a character generally) have had some of the weakest Marvel villains. Boring motivations, completely transparent evil-itude, and... a bigger, more powerful, gray armor suit as the Final Boss? Come oooonn.
So basically everything having to do with the main plot arcs in both Iron Man movies fell totally flat for me, whereas the ancillary stuff in both is what I loved. Testing out the suit prototypes, the Golmira rescue, Tony showing up places he's not expected to be, everything about Justin Hammer/the role of Tony Stark in Homeland Defense, the Iron Man/WM fight, scenes with Pepper/Black Widow/Fury/Coulson, the Hammerdrone massacre, all of that stuff is what I liked, whereas anything having to do with Iron Monger and/or Whiplash was basically just "insert plot element" as far as I was concerned.
That said of course I can't deny narrative inconsistency in it compared to the first. Iron Man 2 was by far the most "oh by the way a HUGE CROSSOVER MOVIE IS COMING" of any of the Marvel flicks, even Captain America despite its subtitle.