2. Dean Ambrose
Although not as blatant as Dolph Ziggler's impending heel turn, dissension has arguably been brewing in WWE's biggest babyface bromance. Ambrose has looked a little shaky since Chris Jericho's disappointing Night of Champions performance, and has been reluctant to trust outside forces ever since. Reigns, meanwhile, turned up to challenge Bray Wyatt alone, with no mention made of Dean's whereabouts. The impending Cell match between Wyatt and Reigns will surely fall victim to outside interference, despite the supposedly isolating nature of the stipulation; but what if Roman isn't undone by a predictable attack from Harper, Rowan or Strowman - but from a much more familiar source. Since becoming one of the most over babyfaces on the roster, it's easy to forget just how captivating a heel Dean Ambrose was. After playing second fiddle to the decidedly less-popular Reigns for a while, now is the perfect time to turn him back to the dark side. It should be relatively easy to book Ambrose's motivation for turning on Reigns. He could be furious at his friend for not making the most of opportunities thrown his way - opportunities Dean himself would have had to fight ten times harder to get. Whatever the reason for an Ambrose heel turn, it would be an incredibly worthwhile risk for WWE to make. It wouldn't just refresh Dean's character - it could even result in a feud that would grant Reigns that ever-elusive sense of legitimacy.