#1 Shinsuke Nakamura
Why would someone as talented and as over with the WWE Universe as Shinsuke Nakamura be on a list like this? While Nakamura is one of the most popular NXT Champions in WWE history, and like Balor has a very interactive entrance theme, he also has one problem that will most likely hold him back from long-term main event success.
The problem with Nakamura is that he isn't great at promo cutting. Sure, he can do a little bit if he has the right person to work with, but he has a very limited repertoire when he is alone. What makes it a little worse, however, is the fact that the WWE Universe is still lukewarm on the idea of a foreign champion, which only complicates things more.
Of course, a lot of that probably has to do with Jinder Mahal's disastrous run as WWE Champion, but Nakamura probably won't fare much better if he can't improve his promo skills and connect better with the audience.