Really, I don't think these films can work.

First off, there is too much legal stuff from preventing these from being made. Of course, we all want continuity but can it happen? Can all the same actors from the individual films (assuming all the individual films will be made) be cast in the team movie? Will the studios allow their actors to reprise their roles in films by other studios?

Point two, it's gonna be a clusterfuck. I have my doubts whether or not all these superheroes together will make a good film.