--It was The Undertaker who initially requested that the announcement for his match against John Cena be delayed until he could see how his body was responding to training in the ring.
Undertaker had a minor set back with one of his knees a little over a week ago and depending on how quickly he recovers, he pitched the idea that if necessary, the match not be confirmed before WrestleMania at all. Obviously, this is the route WWE end up taking, with no announcement made on Monday Night Raw. Cena vs. Undertaker could instead be the result of an open challenge or portrayed as a physical "confrontation" and not an official match. The feeling from Vince was that the WrestleMania card is already so strong that they could not announce the match officially and still be alright.
--For those wondering the idea of Carmella cashing in at WrestleMania HAS been pitched. Both on the Raw and the Smackdown Women's Championship matches. Nothing has been decided, but it's worth noting they've tossed around the idea in meetings. If she were to cash in for the Smackdown Women's Championship it would likely be on Asuka after she won the Smackdown Women's championship.