I actually thought the ending was a great setup for Wrestlemania. You had to believe that if Cena had to win his way into Wrestlemania, he wasn't winning clean, otherwise fans would be blasting Vince for such stupid booking. The ending tonight did a few things. First and foremost, it got Cena into the main event of Wrestlemania. Second, it kept the fued a little more interesting. Third, it made Batista look how he should look. Like an unstoppable monster heel. Cena hasn't inflicted any kind of damage on Batista in their recent little battles. They are building for the inevitable "David v. Goliath" match at Wrestlemania, with Cena winning and the kiddies going home happy.
I've seen people say Cena should have faced Sheamus tonight. Would it have been a more eventful match? Probably. But again, you can't have Cena go over Sheamus clean, because it takes Sheamus' credibility away. Right now, he has the whole "it took two guys to beat me" thing going for him into Wrestlemania with a potential match vs Triple H. You can't believe that Trips wants his Wrestlemania opponent to go into Wrestlemania looking weak.
I think the booking right now is looking good for Wrestlemania, at least storyline wise. Will Cena vs Batista suck at Wrestlemania? Most likely. But it's going to be built up so much that people don't care how good the in ring stuff is. That's what Taker vs HBK is for. That's what Edge vs Jericho will be. Cena vs Batista will be this years Triple H vs Orton. Massive build up and a blah match. But a solid, entertaining story going into the big show.