Most of the popular American comedy movies in the past decade starred "the lovable loser": Will Ferrell, Vince Vaughn, Steve Carrell, Seth Rogen, etc. The difference between those and Kevin James is that Kevin James is pretty fat.
Although all of the lovable loser comedians are interchangeable. They're all the same (ie, shit) which is probably their greatest strength. That way if Seth Rogen turns down the role, they can hire Kevin James without having to change much if any of their script.