My feeling is the opposite. I agree Sting and Undertaker should meet at WM31. Especially if this is to be Sting's only match and 'Taker's last match, this is the logical choice.
So, why are we reading rumors about Undertaker facing Triple H? I think it might be because WWE legitimately doesn't know if Mark Calaway is going to be fighting anyone.....ever again.
If he is wrestling that night, I would think either Sting or Brock Lesnar will be his opponent. If 'Taker isn't entering the ring again, that's where Triple H comes in. He's a legendary opponent for Sting to face....but, consider this: of all the top performers on the WWE roster, who can most easily step aside without having his career plans messed up if Undertaker decides to compete after all?
Triple H, that's who. I don't think he's inserting himself to feed his ego; he's doing it because he wrestles only when the company needs him to....and if plans suddenly change, he can take a seat without losing his place in the hierarchy.
For example, if the company was advertising Seth Rollins for a WM31 match against Sting......what would happen if Undertaker suddenly announced he wanted to face Sting? What would the company do with Seth Rollins, unexpectedly forced out of the match and left with nothing to do at the biggest show of the year?
No, there's only one guy who can: (1) Be an opponent worthy of fighting Sting in his first (and only?) match in WWE, yet (2) Step gracefully aside if he's bumped from the contest.
That's Triple H.
This is it really, isn't it?
Only thing I hope is that IF Taker does get ready and Sting becomes his opponent, that HHH just doesn't merely go to the side and sit it out at a WrestleMania that could well be "the Dawn of a New Era" in the WWE, given the pushes that have happened this year.
I'd love Taker vs Sting to happen. That is a definite being I am a huge Taker mark. But I'd also love if HHH then ends up facing Roman Reigns and finally gets those 2 to go at it, with HHH giving Reigns the rub and letting the latter 'finish off' the Authority once and for all. Seems pretty apt given how it all played out from the Night after Mania 30, doesn't it?