Nothing is off, its just that the element of surpise with iron man the super hero is gone. What made the first one so great was that it was the first one.
I mean the first one had the weakest villan, but it was great because Iron Man was new. Part 2 wasn't as good because it had to follow up the first one which is hard to do. They didn't have a major villan which is kind of hard to do anyway without involving Shield which they didn't want to do, AND like the first one, there wasn't a major "showdown" scene until the end of the movie.
Part 3 has had to follow up Avengers which is impossible to do without the other Avengers. Again, you have villians that are not that great for the simple fact that they didn't want to involve SHIELD. That in itself is a head scratcher though because Colson was inquiring about terrorist organiztions in Iron Man I but they didn't care about what the manderin was doing? Maybe they figured the Iron Patriot was good enough.
At any rate Iron Man is a classic example of it's not new anymore so its hard to feel excited. I think the thing that keeping these Marvel Movies from being great are the villians and how they structure how the super hero and villians interact. In Iron Man 2, Toni Stark spoke with Rourke once before their final fight.
Once you establish your super hero in the first installment you have to focus on the villian for the rest of the sequels. Yeah you need to show the super hero character evolve but that should only be a minor detail and not the jist of the movie. I hope they do this with Thor as the villian should be more powerful and compelling.