#1. Dean Ambrose

According to the Wrestling Observer Newsletter, had Roman Reigns not suffered the illness and vacated the Universal Championship, his opponent at WrestleMania 35 would be none other than Dean Ambrose.
Whether it would be a main event or not, there's absolutely no doubt that it's worthy of a WrestleMania match. They have the history and the story to run it. While it doesn't make sense now given that The Shield are reunited, there are still ways to get to this match.
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Frankly, with Ambrose leaving, there's no better opponent for Reigns right now at WrestleMania than him. Ambrose would have to put Reigns over, but there's no doubt that he would love to on the way out.
If Ambrose is staying, which does seem like a remote possibility at this point, the storyline can take all sorts of twists and turns. Just that this time, there won't be any title on the line. Not that they need it anyway.
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