I don't really get that at all, though I can understand why some may fear it.
Tony Stark = wit and sarcasm. I think that's where most of the humor will come from. The humor will likely be dark and of course situational at times due to the nature of the character. But I just don't see it reaching the FF's satirical level.
I think the movie will be a mix of the old red and gold avenger and the new IM which admittedly I don't know a whole lot about, other than the fact that everyone says IM is screwed up in the current comics.
I get a very Spider-man-ish vibe from this film--it won't be a dark brood fest, but it won't be campy either. It will be what it should be, a close as possible comicbook fantasy film, nothing more, nothing less.
Let it be what it should be and most will be fine. If people start trying to make IM into something it isn't supposed to be (or worse shoe-horning IM into their personal rendition of the character), then the problems will start.