Just a quick thought on the ’13 Rumble. If you really wanted to be crazy and wacky with the booking but keep Rock/Cena, you could’ve had Ryback win the Rumble while letting Punk use the Shield to take out Rock.
Then, you could do the WM18 thing with Rock/Cena being the "Real" Main Event for everyone getting the show & Punk/Ryback being the actual last match (as a side benefit, you’d then placate Punk’s ego and we’d never get Colt-gate & UFC PUNK). Now you could still have Cena/Rock plus you’d have Ryback finally solidified as a legit main eventer and an historic way to end the Reign of Punk.
Then, I guess you could have UT/Brock a year early, maybe? Between those 3 matches, holy crap how much more stacked a WM could you have?
Well the thing is that Cena-Rock was the right way to go from a business standpoint, but it was just a really predictable and boring direction for those who watch the product for the rest of the year. Plus there was way more going on with Punk than just placating his ego at Wrestlemania.