No matter how great Ali could look in the suit or how well he could play the character, we still do not know what type of John Stewart WB is looking for.
If they are not looking for a mentor/mentee relationship from Hal and John, then Ali could fit with any of the rumored choices.
Still, Hal is expected to be joined by John Stewart in the film, and some new fan art makes a compelling case for Ali to be that man.
With there so much interest in Ali currently, WB would be smart to pick him up as a lead of their franchise moving forward.