#3 Roman Reigns wins big at WrestleMania 31
If Roman Reigns had lost to Daniel Bryan at Fastlane it would have reshaped his trajectory, including Bryan getting subbed into the WrestleMania 31 main event, and Reigns taking a step backwards for a time. If there's one thing we know for sure about what really did happen over the years to follow, it's that the powers that be at WWE were committed to ultimately getting Reigns over at the highest level.
So what would Reigns have done had he not challenged Lesnar at WrestleMania 31? It's unlikely he would have slipped so far as to have simply swapped spots with Bryan, and participated in the Intercontinental Championship Ladder Match that opened the show.
He may well have worked opposite someone else from that match like Wade Barrett one on one, or conceivably have been booked opposite Dean Ambrose to tell a different story among Shield alumni. Otherwise, someone like The Big Show could have been pulled from the Andre the Giant Memorial Battle Royal to work Reigns.
Whoever the opponent and whatever the stakes, we can safely guess Reigns would have picked up a big and decisive victory to get him back on track toward ultimately becoming the face of WWE.