As another poster pointed out there are black and Latino superheroes already out there, however, the problem has been in the comics and on the current comic book movie boom not developing and promoting these characters so they can have a movie or franchise. Black Panther has all the ingredients to be a franchise for example, but nothing seems to be crystallizing around putting him on the silver screen.
I would rather see films based on these characters than just browning or blackening Spider-Man. However, I wonder if majority white and global audiences could accept the idea of a black or brown hero as an 'everyman' or care about his relationship with Mary Jane, which was a significant part of the previous films.
I am disappointed that a lot of the black superhero/comic characters that have received movies over the last 20 years have been original creations or not tied to original comic book characters. You've had Meteor Man, Blankman, Catwoman, and Hancock in that vein. Only Blade, Spawn, and Steel have been derived from source material. DC, Marvel, or Image hasn't shown much interest in exploring their rich, though often untapped or underdeveloped reservoir of non-white characters, and then reinforcing the movies with more focus in the comics. And there is a tendency to make black superhero movies comedies, underlining the idea that a non-white superhero, specifically, a black one is a joke. And I find that very sad, yet telling.
Potential franchise characters: John Stewart, Black Panther & Storm, Deathlok, Blue Marvel, Static, Icon & Rocket, Hardware, Blue Beetle, Black Lightning & his family, War Machine
Other characters that I would like to see at least get the big screen treatment:
Luke Cage (as long as they don't make him stereotypical)
Isaiah Bradley (Captain America)
American Way comic series
Black Jack (Arron Day)