In all honesty, a comic book based AVENGERS would have a better longevity... the comics still swap hands with collectors, artwork is timeless and comic book art is very very cool.

Film??? Well its been and gone already hasnt it?

Yep the movie has been and gone but the artwork is based on the movie and has the actors from it, so it would make sense to have as much of the film tie in as possible.
If it was comic book based there are so many other characters both good and evil to have in there and custom art and music etc would have been perfect.