I'm a little wary about focusing the movie more on Tony Stark if I'm being honest. Downey was great in the role in the first film and in the Avengers but Iron Man 2 relied too much on Tony's wacky antics and failed miserably on a creative level.
You don't like Iron Man if you don't want the next movie to actually focus on Tony.
I'm not saying that. As pointed out, Tony had nothing to do but basically goof around for most of Iron Man 2. I think they played up Downey doing his shtick too much and it just didn't work.
In Iron Man 2, Tony talks about manufacturing world peace but we never see it. There actually felt like there was less action in Iron Man 2 than in the first movie and I didn't think that was possible.