Would you appreciate Taker/Lesnar like everyone is clamoring for, because frankly, I'm sure Batista would work much more than Taker will.
There's a HUGE difference between Taker and Batista & Lesnar. Lesnar & Batista are, for all intents & purposes, a couple of high paid mercenaries who don't have any real love for wrestling. Taker worked his ass off, injured or otherwise, for well for nearly 25 years. I think he'd still be out there much more frequently, even at 48 years of age, if the wear & tear hadn't caught up to him. I'm not hating on Lesnar or Batista for leaving, don't get me wrong there. If they weren't happy or wanted to do other things, more power to them. But Taker's a wrestler, always has been & always will be at heart, even if his body's all beat to hell and that counts as a lot with many fans. Taker's an old school guy with an old school mind who came up through wrestling the old school way; busting his ass to pay his dues whereas a lot of more modern guys, such as Brock Lesnar or guys out on the indie circuit in general, or even guys who got into wrestling during the Attitude Era, like Batista, operate with the mind set that is owed or should be handed to them. Taker's a dying breed, people know it and it's part of what makes a lot of fans respect him.
Also, as for Batista, as others have pointed out, Batista isn't The Rock. He doesn't have that level of star power, he never did. The Rock had a level of charisma and genuine star power that brought something unique back to the table. While the novelty, for me at least, of The Rock returning all triumphantly has worn off, he's still a bigger star than Batista ever has been. That doesn't mean that there's still not money to be made off the guy, but we all know how fans have changed over the years. As has also been mentioned, there are some walls to overcome if WWE wants to really make Batista's return as much of a success as possible. A big part of that could be where Batista ultimately lands against at WrestleMania. For instance, Batista just won't be able to walk in, flex a little, shake the ropes and stomp around while expecting people to be amazed by his physique without being bombarded by "Daniel Bryan" or "CM Punk" chants if he winds up winning the Royal Rumble. A lot of fans simply aren't going to drool over Batista as this mega star going up against Randy Orton, if that's what the plan is, just because WWE might want them to. Batista's a big name, but he's not Cena or Rock big, nowhere close really. Oh, I'm sure he'll get a massive pop when he returns on Raw, the place'll be electric and buzzing with excitement over the novelty of seeing one of the bigger starts of the last decade back in the ring. But once that wears off, and it will after a week or so, then fans will have more of an idea about what his role will be and who it'll be against. And if they don't relish the idea of Batista vs. Orton,
IF that's what the idea is, for the strap at WM, they'll let WWE know about it and the result could be lackluster interest in the first WWE World Heavyweight Championship match at a WrestleMania.