#3 The Rock's return

Let's be honest here.
As great as The Rock's rumored return in The WWE sounds, it comes at a cost and make no mistake that the cost is a big one. In fact, if WWE goes with The Rock versus Roman Reigns for The Universal title at WrestleMania 35, it could end up being received the same way that Cena versus Rock part two was.
Breaking Vince Russo and Jim Cornette update HERE.
Of course, the circumstances will be different and the problem will this time be that The Rock's spot belongs to someone else, but that doesn't mean it will be any less god smacking for the WWE. It could even lead to a boycott or general loathing of the pay per view in the same way that WrestleMania 30 and 32 originally were.
In the end, Rock versus Reigns does sound like a money match, but it's at the expense of everyone else on the roster. While that might have been a good idea if WWE took the title off of Reigns and turned him heel in the process, it's not going to work when you consider that Reigns has been in this position too many times for it to mean anything.