Its well known that DC puts out much better written and consistant feature length animated movies based off their major/less known characters and storylines and having seen almost every DC Original animated movie released from 2007 till 2012, i have to say that ive become more of a DC fan than a Marvel one even though i grew up on Marvel Comics not DC Comics.
But lets just say if Marvel wanted to follow DC in the animation department and seriously compete with DC and decided to take their major/less known characters and storylines convert them into 2 hour long feature length animated movies, then what ones would you like to see?
Mine would be the following:
Secret Wars I & II
The Infinity Gauntlet
Age of Apocalypse
War of Kings
Avengers vs. X-Men
I think if the following were very well written and well animated especially based on the artwork on what crossovers they were actually based on then i think Marvel can finally give us some awesome animated movies for everyone to enjoy.