I mean we have seen the suit case armor but should he have more of his specialized suits? In the movies should we see an Underwater suit or his Stealth suit or is that too much of a stretch?

I don't see the point, honestly. I never liked the idea of underwater armor. But stealth? Maybe.

" hulk buster armor for the avengers movie would be cool "

there's a very thin line with different armors, if used the right way it would be pretty cool.  If used the wrong way, well then you have Batman Forever and Batman & Robin with their super "why didn't i use this from the beginning" suits

i always thought he should have stealth on all of his armors. I dont think a specialized armor should come in to play in the movies until the avengers movie (preferably the sequal)

Wouldn't it be cool to see an Underwater Iron Man suit IDK destroying a submarine?

yes, it would be more accurate to the comics in he had many armors