Not sure I'd rank him in the spot as Schwarzenegger, Stalone, Willis and them. What's the most bad-assness Snipes has to his name (in the same as others, not playing a comic book character)? Passenger 57?
Terry Crews, who has among the least cred for this, actually got Snipes role. His role was made for Snipes but Snipes was in court, under house arrest when the first EX was filming and was considered a flight risk(?) so the judge wouldn't let him out country to film.
And as Admiral Young
said, a WWE and MMA person are in the movie which means Snipes has loads of cred for Expendables.