#1 WWE can't force the fans to cheer for Reigns
Ever since The Shield broke up, WWE has done everything in its power to try to make Roman a fan favorite. This plan backfired gloriously, as the last thing the WWE Universe wants is for WWE to force them into liking someone.
Also read: 3 rare occasions when Roman was cheered
Although at first, Reigns was heavily cheered when he defeated Randy Orton at SummerSlam 2014 in the biggest win of his career till date, fans soon realized that Reigns was being shoved down their throats. His Rumble win was booed out of the building and even The Rock's presence couldn't save Reigns from fans' wrath.
WWE's numerous attempts to force the fans to like Reigns have failed, and they realize this fact. This will be the biggest factor to take into account when they turn him heel. The most likely scenario would be a ruthless Reigns turning on a babyface Rollins after Mania, and continuing their rivalry from years ago, with the roles reversed this time.
Also read: 3 fresh feuds for Roman upon his return