Rather than including Marvel in the parks, what if Disney simply included an EPIC comic book store at Downtown Disney? It can replace that shop attached to the AMC (I forget what it's named) to fit in with the "cinematic-theme" nearby. The shop (Marvel Superhero Center) would be nothing but Marvel, ranging from comic books to movies to action figures to collectibles of all variety. The store would be extremely well-themed, kind of as if guests have stepped into an over-sized comic book or something like that.
Would you rather have an elaborate Marvel store or an elaborate Marvel attraction in either park? I'm neutral.