As previously reported, the promo between John Cena & Roman Reigns last week on Raw was planned and scripted. Backstage reports indicate that Vince McMahon actually spoke with both wrestlers personally about what he wanted them to say in the promo they had last week on Raw. 
Each wrestler was given an outline of the script on the Friday before Raw last week and told them to work on their delivery. Based on the opinion of the public as well as the WWE Universe, Cena’s delivery and part of the promo came out significantly better than Reigns, but that didn’t really surprise a lot of people backstage.