Rayzah
I'm Everywhere you ain't never there
Wouldn't it have been more of a surprise if they never mentioned Undertaker at all?
Have Cena decide after Fastlane that since he lost the WWE title match, he's issuing an open challenge at WrestleMania. Then they build it up with everyone speculating who's going to face Cena. At WrestleMania, Undertaker answers the open challenge and they have the match. The match still happens the same way they want it to, but you don't have Cena running around every week begging for Taker to do something and nothing happens.
Damn that would have been dope. But wwe is too scared to do surprises like that they need to make sure every big name is teased so they can secure people checking in.