John Cena versus Roman Reigns is the biggest match in WWE's future. The promotional build for it should start now, in preparation for a mega clash at WrestleMania 32. It is something that WWE has been considering for a long time. As far back as a year ago, insiders were describing Reigns as WWE's hand picked successor to John Cena. The long term view is that Cena will be moved into a "champion emeritus" spot and Reigns will take the franchise champion position. For that to happen, it is inevitable that the two men will clash at some point. Cena has defined the last era, lasting a full decade. Going forward, Reigns will define the next era. The samoan had a shaky start to his planned elevation, but the ship has steadied. The fact is that he's had the match of the night for three pay per view shows in a row starting at Fastlane. He's a star and the star reactions are starting to come. John Cena meanwhile is waiting for the next great opponent he can headline Mania with. It has been two years since the biggest star in wrestling worked the main match at WrestleMania. Cena and Reigns are destined to main event at WrestleMania 32 and the build for that may already be underway.