2012: Turning John Cena Heel
This would have only worked for a short while, as John Cena was integral to WWE's business in the first half of the decade. But despite the support from kids, a temporary heel turn from Cena would have been huge in 2012. While he played the pseudo-heel during his WrestleMania program with The Rock, the subsequent defeat should have sent him on a serious downward spiral. John Cena even promised some time off following a hellacious Extreme Rules match against the returning Brock Lesnar, at the end of April.
Had Cena followed through with his promise, CM Punk and Daniel Bryan would have had some well-deserved pay-per-view main events to their name. A proper reaction to his crushing loss to the Brahma Bull at 'Mania would have been a welcome change, instead of a tired feud with John Laurinaitis and the Big Show. Heel Cena vs Face Punk would have brought a different dimension to their multi-year rivalry before the alignments would eventually be fixed and John Cena sees the light again.
If there was ever a year for the much-talked-about heel turn to happen, 2012 was the one. From the 'Embrace the Hate' storyline with Kane and the burial of Zack Ryder to defeats and beatings at the hands of The Rock and Brock Lesnar, WWE seriously missed a major opportunity for some excellent television. It would have also indirectly boosted CM Punk's WWE Championship reign, by making him the top babyface in the company for a few months.