If we didn't get Steve's scenes and Thor can jump in despite being stranded from Earth, (and I've scene things on the internet about Tony-Steve tension regarding Howard being cut, take it with a heap of salt, I haven't got the source at hand), I can't possibly see them dragging Tony into a suit kicking and screaming. The Avengers was far and away too fast paced for any of it the first time (to its detriment, I would say, but not too much); can't see them slowing down 2.

(Also: hear hear on the blowing up the suits. And RDJ's body. I hope to look that good at his age.)