Since this was the only thing easily wrongly done with the show, I'm pretty sure it has to do with Cena. He has a lot of backstage power and he did the exact same thing to the Nexus back in Summer of 2010
The comparisons to Sandow are ridiculous. Sandow's Money in the Bank Cash-In stood in the way of WWE's greater plans for title unification and they had to throw it away to move on with the greater story. There was no way the TLC match was going to ever be Randy Orton vs Damien Sandow, and you people are completely ignoring that fact.
This match helped Wyatt because it was a WrestleMania payday against the guy who was wrestling The Rock in the main event just a year earlier. Wyatt was undefeated on PPV in singles competition (maybe all competition) going into this, with clean wins over Daniel Bryan and Roman Reigns.
This match was all about paying back Cena and his fans for putting over Randy Orton in three consecutive PPV title matches to build him up for Daniel Bryan. If you look at the larger scene: Bryan beat Cena clean, Wyatt beat Bryan clean, Byran beat Orton and Batista clean, and Wyatt was the odd man out without a loss here. It was all about setting the equilibrium of trading wins with each other. Wyatt was due a loss, and it's better to lose to Cena than the Brooklyn Brawler.
Wyatt's gimmick isn't that he's undefeated. It's that he's The Joker in the Dark Knight. He's powerful even in loss. He doesn't need to be undefeated and now his character doesn't have to be all about that.
I highly doubt this feud is over and that Wyatt isn't going to come out of this feud looking better. The Undertaker never beat the Ultimate Warrior either. This match didn't hurt Bray at all.
If you think it was just all "CENA WINS LOL" you're not looking at the bigger picture.