[Jeritron]

I hope Edgar Wright and Simon Pegg make Ant Man before Avengers, so they can work in a minor role or cameo for him.
Obviously he's not going to be a major player but he could be a cool sidekick or one-scene gag.

I have a feeling that movie will be good. Edgar Wright is great, and Simon Pegg is perfect for that type of role. The smaller the movie the better. It should be made in the same spirit and scale as Shaun of the Dead and Hot Fuzz.

I don't think Hawkeye or Vision should get their own movies, but they could work them into any potential Avengers sequel easily.

I think getting a movie like Avengers off the ground is a pretty ambitious thing, and unexplored territory. They should stick with Cap, Iron Man, Thor and Hulk (and maybe Ant Man) the first time around. It will be hard enough to make all of those elements come together, nevermind introducing new ones at the same time.
Lesser Avengers seems like a sequel thing. If Vision, Hawkeye or anyone else is shoved in there it's going to feel bloated as hell