#5 Johnny Gargano
It might come as a shock to many fans if this match happens. Though Cena buries a lot of superstars, he has done a tremendous job as far as building some of them up is concerned, like Kevin Owens, Daniel Bryan and Shinsuke Nakamura just to name a few.
Johnny Wrestling has been fired from NXT but that doesn't mean he is gone from WWE permanently. In the near future, he has to make his main roster appearance, and what better way than facing Cena at the Grandest Stage of Them All. The fans have witnessed his athleticism at NXT Takeover: Philadelphia, and it fits perfectly to be the next Daniel Bryan, which would work well with Cena.
For those who don't watch NXT, this might not be a huge name yet, but two years down the line, they will definitely agree that there would be no better way of him debuting than taking out the leader of Cenation.