With all the possibilities available to an Avengers movie there is no way in my opinion that it can not be one of the greatest comic book movies/movies ever made. With the characters and material in the Avenger world such as Captain America, HULK, Iron Man, Black widow, Wolverine, Spiderman, THOR, Dr Strange etc etc etc...the possibilities are endless. My suggestion for the movie is to be more character driven and realistic than story driven and comic book like. It seems pretty obvious to me that that movie will consist of Captain America, Iron Man, Hulk, Thor and Ant Man (Black widow and Wasp possible also)
and so far they have Ed Norton Jr. and Robert Downey Jr. playing characters. In my opinion that is a great start to any kind of movie and a great start to a great character driven movie. I don’t believe it should be "dark" like TDK was but it should show the good and bad parts of being a super hero. As far as the story itself it is pretty obvious that it will be about the team coming together and such, as far as the bad guy(s) that one is tough. At some point the team will be fighting the hulk in some way I am guessing but as far as a primary enemy it is going to have to be some kind of highly financed terrorist group where all there powers will be needed and tested, I can not see them going with a "super villain" unless they go with something like skrulls/super skrull or similar. To be honest I will probably see this move at least 5 times in the theater when it comes out no matter who is in it or what it’s about. Well anyway that is my suggestion anyway....