Groot and Rocket Raccoon are great supporting characters but like Marvel Comics is finding out right now. Support characters don’t necessarily sell. I suppose you could point to the international success of Mr. Bean that would validate claims that you could have a star with a non speaking part. This film however would have to be serious in some respect while MR Bean is comedy. Two very different genres.
I think the fact they took a 3rd string character from the comics and turned him into one of the best selling dolls/Action figures of the year is still a pretty good accomplishment. In the spirit of compromise though I’d be willing to watch Vin Diesel say nothing but “I am Groot” in the next Fast and Furious movie. Thanks to the folks at MTV International for the hook- up(I’m 45 and shouldn’t be using that slang…humble apologies.)