#1. A dream match that we've never seen before
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Remember a few years ago when WWE teased Roman Reigns vs Goldberg? There's a high chance that it was done by design, so they could set up a dream match down the line. While Roman Reigns may not necessarily be his set opponent, there's a very high possibility of it happening.
Morevoer, if they have a match of that caliber, it's a guaranteed headliner that doesn't even require a title. Sure, match length is something that would likely be problematic with Goldberg, but Roman Reigns is good enough that he can carry the match.
Is this man the funniest man in wrestling?
Plus, if it's anything like the short WrestleMania 33 Goldberg-Brock Lesnar match, then there should be nothing but excitement. Goldberg probably couldn't pass up the opportunity of facing a younger dream opponent such as Roman Reigns and would have been more than happy to come back.
It works for WWE too, because Roman Reigns would get another massive victory over a legend.