Honestly the more I think about it, the better it is if Reigns was to turn heel, and not in a "herr derr evry1 shuld b heel" kind of way.
Mainly because I look at the roster, the heel side is basically Seth Rollins, Kane and Big Show, and the face side has Cena, Bryan and Orton....I mean what would you rather see? Him being paired with ring generals where he could build up a resume of great matches that'll eventually turn the naysayers around and he'll do nothing but learn.
Pair him with the heel side and it'll bomb imo. Mainly because WWE has no real heels that'll make him.
The reason why Cena was put on Raw in 05 was to pair him up with all those ring general heels that year.