Gotta have something for Shane to jump off.
Also it's so perfect that Roman would beat Undertaker, as in, it'll be the least impactful loss of Taker's career. The streak is over. Who cares if you're second to something?
He still has weight. Do you hear the crowd reactions when he is on the show and when he is face to face with the Reigns?
Also, WWE put up a poll of fan interest in what Wrestlemania match and its above Goldberg vs Lesnar. There are actually 4 matches with more interest than that match according to that poll.