Braun, Corbin, Big E, and Nakamura. Joe has a shot. The rest are wishful thinking. The main event scene hasn't been this dense in a while.
It's going to be very hard to come through as a new baby face champion with Roman and Balor pretty much cemented as the next faces of the company and Cena still lurking. If you want to get through as a pure working wrestler, you have to be a better wrestler than Styles, Rollins, and Cesaro. Owens, Ambrose, Ziggler, Miz, and their friends are probably going to be upper mid carders with occasional title programs, you'll have to overcome them. Then there's the veterans and part timers - Cena, Orton, Sheamus, Jericho, and the rest.
Big E, I think with New Day getting over the way it has, he now has world title potential. Before he was just a big guy that could move, but didn't really have a personality (not on TV anyway). Now we know he's a funny guy, and him being a remarkably good wrestler has kind of taken a back seat (for all intents and purposes has been in the business for only 5 years). He does a lot of cool power moves and will have immediate credibility from his New Day run as soon as he goes singles.
I remember watching the Y2AJ/New Day match from last year and remember thinking Big E looked like a million bucks in that match. I knew that guy was going to be a world champion. He's got the look, he's got the charisma, he's got the wrestling ability. The guy can do it all.
Braun and Corbin are being groomed for it. Again, big guys that can work. Braun is the faceless monster, Corbin is the typical arrogant heel. These guys are both very good at their roles. I expect both to be world champions within the next 12 months.
Shin, this guy has an outrageous amount of charisma, and is a sensational wrestler as well. It would be a crime to never give him a run with the title.
Wyatt, I have no faith they'll figure out how to use him ever. Miz quite frankly has earned a title with his stellar heel work, but I don't see it happening. Zayn, they could tell a GREAT story with him but I don't think his charisma is high enough to have the people rally behind him like Daniel Bryan. Rusev, again, has probably earned a title run but I can't see them raising him from his current position that much. He got clowned by Roman and Cena, and is a great example of how hard it is for someone to get into the main event scene these days.