^Great idea, but never going to happen.
I have the same problem with Sting facing Taker for the streak as I do with Jericho facing Take for it. No one is going to believe that either Sting or Jericho can take Undertaker to the limit given the match Taker had with Triple H this year.
It really depends, I don't see Chris Jericho as a viable contender to the streak because pretty much everyone has defeated Jericho (although this doesn't effect his status as a main eventer because of his in-ring and talking skills, which define him as a performer). No, you need someone with near equal characteristics and "lore" factor to compliment Undertaker in the streak matches these days.
Although most of the hammy supernatural stuff has been phased out, there are some clear traits involved with Undertaker that define his mythological status: (which WWE is fiercely protective of)
- He has never lost a match at Wrestlemania.
- He has never "officially" tapped out.
- He disappears for extended periods of time, doesn't break kayfabe if he can help it, by doing things like giving interviews or attending WWE publicity events.
- The creation and pioneering of the Hell in a Cell match is attributed to him from a storyline perspective.
Triple H worked two years in a row because he has almost equal footing with Undertaker. Trips has held 13 world titles, he's won more Hell in a Cell matches than anybody else, he's the boss' son-in-law, etc. WWE will emphasise the more interesting qualities about Taker's opponents, especially if nobody is really buying that the other guy has a chance (which is always true, because the streak must remain intact) for the purpose of suspending disbelief and selling PPV's by offering a incredible match opportunity (which usually exceeds expectations).
With all this in mind, the performers on the roster currently that are feesable opponents for Undertaker are:
The Big Show