I hope we do not get Undertaker vs. John Cena. I've wanted Undertaker to retire for a while. He could've stopped at 20-0 and his legacy would've been amazing. He could've stopped at 21-1 with the passing of the torch to Brock Lesnar to make him the new threat, so when Lesnar gets taken out for good, they'd have a new mega-star. His legacy would remain... but beyond the 21-1, his legend is starting to slowly lose his mystique and every match is showing he isn't as good as a performer as he once was. Maybe there is an argument to say that Undertaker is losing his mystical powers and becoming mortal but I doubt that's the plan. He has done everything he can for the WWE; he owes nothing. Yes, he might still enjoy wrestling (and that WM pay cheque) but enough is enough. If he has to wrestle one more match, give it to someone who needs a win to establish their career. Finn Balor absorbing the soul of the Undertaker to fuel the Demon King would be great. Cena is also in a position where him winning isn't needed any more. He should give the rub to someone else and take his place when he is done. He can't remain the top draw forever.
The only other things I care about is the Battle Royale being on the main show and the overall scheduling of Wrestlemania. The last WM sucked because we got some good matches on the pre-show and time wasted on the main card for things the crowd doesn't care for.