#2 John Cena
John Cena does not have an opponent for WrestleMania 35. It was rumored that he would take on Lars Sullivan at the show of shows, but because of a panic attack that Sullivan suffered, the match had to be pulled from the card. And as a result, there's a slot open with regards to Cena's opponent for the grand event.
I would say that Roman Reigns is the ideal opponent for John Cena on such a massive stage. And this is because the two men did have a rivalry of sorts, that fizzled out way too soon because of Cena's breakneck filming schedule. There's unfinished business between the two men that could develop into a great angle.
Cena vs. Reigns is a match deserving of a stage like WrestleMania and I think that the previous match felt way too insignificant to me. They will tear the house down.