#1 Retiring John Cena

While defeating John Cena is still an accomplishment in WWE, especially on a stage like WrestleMania, it probably won't be enough on its own to build momentum for The Fiend. That's why the company needs to look into making this a retirement match and making Bray Wyatt the one to finally end The 16-time champion's career.
Of course, losing Cena would be a big deal for WWE and might seem a bit short-sighted, but it would do wonders for the career of The Fiend. Beyond that, it would be the perfect passing of the torch moment that finally lays Cena's era to rest and allows The Fiend's era to begin again.
That's a lot of magic to tell in one story, but the company has more than proven that they are capable of it. Sure, it's not the match everyone wanted and it's not for the Universal Title, but retiring Cena is on a whole other level of momentum and will create a path for The Fiend to get back on top.