#3 Seth Rollins
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As tragic is it is that The Shield won't be reuniting if Dean Ambrose leaves, there is a certain upside to it. Seth Rollins and Dean Ambrose have long been associated with one another. Even when Ambrose did return, he aligned with Rollins and then turned on Rollins.
It's interesting because their feud was originally supposed to culminate at WrestleMania 34, presumably with Ambrose turning heel as well. However, their feud quickly went south after finding initial success.
Their match at TLC is best not spoken about. The rumours seem to have suggested that even Vince McMahon was furious with the bout. With Ambrose gone, Seth Rollins can have a 2019 completely away from The Shield and no association with them.
It might help his singles stardom even further, as he's clearly being primed to be the guy in WWE for 2019, presumably replacing Roman Reigns until he comes back.
Major rumor about recently released stars HERE