Black Panther, because he's already an Avenger and could tie-in to the shared universe, and also because of the success/quality of the Blade films (well, the first two) and Panther being a similar character (semi-obscure to the general public, martial arts action).
I like the idea of a Heroes for Hire film with Iron Fist and Luke Cage also.
Originally posted by MF DELPHYouTube video
I like the idea of a Heroes for Hire film with Iron Fist and Luke Cage also.