#1 'The Fiend' Bray Wyatt vs Roman Reigns (Universal Championship)

Well, it is happening. As mentioned earlier, the main event scene on SmackDown is very limited and there aren't many booking options other than to flip the two biggest storylines on the Blue brand. After The Fiend succesfully defeated Daniel Bryan in a Strap Match at Royal Rumble, he is looking for new victims.
Cody Rhodes' uncle is a WWE Hall of Famer. More details HERE.
While Bray Wyatt might face a couple of placeholder challengers on the road to WrestleMania, all signs point towards Roman Reigns being the one who will have a Universal Championship match at the Show of Shows, despite not winning the Royal Rumble match.
The Fiend will want to 'hurt' Reigns after the Big Dog soundly defeated Wyatt inside Hell in a Cell during their 2015 feud. But the 4-time world champion will not back down, as he will be looking to win back the Universal Championship he never lost. Reigns did not even get a rematch for the belt since his leukaemia returned and he had to relinquish it.
Despite what some fans might think, Roman Reigns should be in this position at WrestleMania. But whether this match main events the show is a different question, with Drew McIntyre vs Brock Lesnar possibly being the better option for the show-closing spot.
Also, the outcome of this bout could play a pivotal role on how the fans percieve Reigns, Wyatt, and the match in general. If WWE decides to take the title off The Fiend here, it has to be in a creative way.
ALSO READ: 5 WWE Superstars who could challenge The Fiend for the Universal Title