The problem with this year's WM is it will end on a flat note if it's Reigns cleanly pinning Triple H to win the world title. Everything is set up nicely regardless of who wins the other matches:
Jericho has been on great form after turning heel. They'll both probably be in a ladder match with Zayn, Miz, Ziggler, Owens and Neville. The talent there should make one hell of a match. Lesnar should bring the best out in Ambrose. McMahon/Taker will be a crazy Attitude Era throwback, complete with guest appearances. Likely the best women's match in WM, maybe WWE non NXT PPV, history. A big New Day entrance and toilet break second divas match to round up the show...
A double turn in the main event would rival the last two in giving a memorable ending. Can't see it happening though.