Use whatever criteria you want. I'm ranking mine based on how well I think they'll do on the main roster. I'm definitely not ranking on favorites, as two I love among the best are in the bottom.
1. Bayley. The absolute best white meat baby face the come along since John Cena. She can BE the female John Cena, and I mean taht in all the best ways. I really think she has the potential to be the biggest name in women's wrestling since Trish Stratus. She's incredibly likable, as a person, gimmick, and wrestler, and is a fantastic positive role model to young girls (which, as a father to a 3 year old daughter, is becoming increasingly important to me). Plus, I mean, have you SEEN the house show interactions with Finn Balor? ****ing adorable.
2. Samoa Joe. He could have very easily gone straight to the main roster like AJ Styles and fit in perfectly fine. Unlike some on the internet, I absolutely do not think going to NXT is a "demotion" or "insult" or any bull**** like that. He's done great work there, especially as a heel. I fully expect him to debut on the RAW after WrestleMania after losing to Balor at Takeover: Dallas. Speaking of Balor...
3. Finn Balor. He's got the look, the theatrics, and the in ring performance down. The only ting he's missing are the mic skills, which I really hope he spends time on while at the Performance Center. Granted he can get over just fine without being a world class talker, but he should definitely do what he can to up his game. I expect him to be on the main roster by the end of the year.
4. Apollo Crews. I think he has the best chance to be the big black star they always seem to be wanting but haven't pulled the trigger on (assuming Big E doesn't grab that role first). He too needs to work on his promo skills, and some general polishing. Probably a 2017 call up.
5. American Alpha. These guys are the more charismatic reincarnation of the World's Greatest Tag Team. Chad Gable's a bit goofy, but it plays well, and Jason Jordan is very good at everything he does. I think they'll win the titles from the Revival at Dallas (a team I haven't quite made up my mind on) and hold them for a while. Actually, I hope for a long feud between the two teams before either moves on to other things.
Just missed: Asuka. She'll be on the main roster sooner than later. Not much she really needs to work on!
1. Elias Sampson. Just no. Everything about this guy. No.
2. Baron Corbin. Stupid tattoos, stupid jacket, stupid music, stupid gimmick, and the blandest, most emotionless unchanging dull face since Ted DiBiase Jr looked terrified at all times. I see absolutely nothing appealing about this guy. Of course, he fits Vince's prototype of big guys, so he's guaranteed several attempted pushes on the main roster.
3. Enzo Amore and Big Cass. I might catch some flak for this one. They're very popular, both at shows and on the internet, but I just don't see it. Cass is bland and Enzo is too over the top. Granted they've developed some character depth in recent weeks, but what are the odds they'd get the time for that on the main roster? Of anyone on my bottom list, they're the most likely to be proven wrong. I enjoy being proven wrong.
4. The Vaudevillains. Now these are two of my favorite guys in NXT. They're both entertaining guys, with Simon Gotch the particular stand out. Aiden English has also improved lately, adding some muscle definition that'll surely appeal to the TV guys. But the gimmick, as unique and entertaining as it is, is very small timey. I just see them very quickly dropping matches to the Social Outcasts and makeshift teams like Fandango and Jack Swagger on Main Event.
5. Tye Dillinger. The guy's talented and well liked backstage, but he's been in developmental for what, the better part of ten years? If it was gonna happen it would have by now. He had an incredibly brief stint in ECW as Gavin Spears--I'd be amazed if anyone remembers. He's just one of those guys that should enjoy what he gets while it lasts.
Man. I hope other people post in this thread.