Will Sting return to the WWE?

Over the past several weeks there have been rumors and speculation that Sting may make an in ring appearance at Wrestlemania XVII. At 51 years old I don't think it would happen, but if this match were against The Undertaker, it would be one hell of a match. The Undertaker is getting up there in age as well, and with his Wrestlemania streak coming to a soon end (Personal Opinion) due to his soon retirement, I'd like to see him pitted against someone such as Sting, Kevin Nash, Booker T, or any of the old timers. The WWE has been quite boring lately, and they need one spectacular card in order to get the ratings they need at WM. Who do you see Undertaker facing at WM? When  do you think he will retire? There are already rumors that Edge will be retiring soon, and from what I have been seeing he hasn't been giving 100% in his in ring performances. This could very well be that he don't like the way the WWE is heading with it's planning. My prediction is at WM, all of the young guys will emerge as champions, which brings me to one last question. Why in the hell are they pushing Alberto Del Rio so much?? This guy has one move, which doesn't even seem to do much damage to anyone, although everyone who has been put in his armbar has tapped out....