A gimmick where he invades WWE events and gathers up fans? That hasn't been done before..
They should just have him jump the barricade and start interfering in matches and masterlocking people to death in the clothes he was wearing in that video. I remember he did just that about 6 years ago on SD during the Raw vs. SD wars for Survivor Series with Edge, it was fucking awesome. Seriously, it's so easy to get people over if they just book them right, just like HTK alluded to earlier. They booked Sin Cara strong and he turned out to be a strong character who got a good reception. And I'm not talking about these stupid ass shitty monster pushes we see of roided up failed ass football players and bodybuilders they try every year. Like the great one himself said, people see through phony shit like that, thus they won't cheer. Push entertaining, passionate people with talent and you get results.