^That's really it, D'Z. There's really no Roman Reigns hate, he's sadly become symbolic of WWE's booking.
He's a symbol of the WWE Front Office thinking they know better than the fans. He's a symbol of Vince thinking 1980's booking still works in 2013. He's the clear "chosen one"... and that's the last thing a fanbase who know has a reason to believe that their voice matters wants to hear. Joe Anoa'i is just an innocent bystander in the whole charade.
Shoot, WWE wrote an entire storyline about this very thing, it's called The Authority. They screwed Bryan out of the title to give the title to the hand-picked "chosen one", Randy Orton, because he looks good on billboards and draws and "they know more than the fans do". And it really did work to perfection in the end, it got Daniel Bryan and Triple H insanely over. Don't see why they're clearly doing it in real life while the fans see right through it, that was why the angle worked and this doesn't.
So much of it is adversity, kayfabe or otherwise. Fans love an underdog. That's why Daniel Bryan is so over - he's fun to watch, but he's spent the last year with a legit injury losing the title that he and the fans worked so hard to obtain. Then he comes back and has a ready-made redemption story. See also: Dolph Ziggler, who just got screwed over by the Authority on top of all the times he's delivered in the ring and got jack shit to show for it. With Roman Reigns, he comes back from a hernia and says "I'm winning the Rumble, buhlee dat". Where's the story? Where's the emotional investment? It's what makes this whole thing so see-through. (which is sad since we all called this in June and were happy with the idea then)
There's the matches and promos factor, but really, that should be easily correctable. Shit we saw Brock hit 187 suplexes and we all loved it, why should Reigns be criticized for his "3 moves"? And his promos usually ooze coolness and the "it factor" you talked about. It's not like this dude is Lex Luger at all, the guy's one hell of an athlete and has SO MUCH going for him.