#4 CM Punk doesn't turn heel and his WWE Title reign ends in less than a year at the hands of John Cena
One thing that would have been certain if John Cena turned heel in 2012, was the instant reversal of his fortunes. His "rotten" year would have been quelled by a WWE Championship victory within a couple of months. Due to this, CM Punk's title reign would not have lasted 434 days.
Nevertheless, Punk would still have been the top babyface in WWE. He turned heel because The Rock needed to defeat a villain to win the WWE title at Royal Rumble 2013.
Hence, Punk would have remained as a face and Paul Heyman wouldn't have aligned himself with the Straight Edge Superstar. In fact, Heyman may have been a part of John Cena's stable and managed the younger talents in it. Meanwhile, Cena's subsequent run on top would be largely uninterrupted for a few years, barring a couple of feel-good title changes.
With every fresh title win, he'd inch closer to the record of 16 world title reigns.
This would have been similar to Triple H's reign of terror on RAW from 2002 to 2005, only with more shenanigans. Anyway, CM Punk as the face and John Cena as the heel would have made their feud even better.