I don't think this stands.
You could put The Rock in against CM Punk, Taker, Orton and it would do the same this year even if there is no Cena involved. The big time feel is gone with their first encounter. Cena isn't much of a PPV draw. The only reason the last two Wrestlemanias performed was because of Rock.
Rock vs. Brock is the biggest match possible.
People don't care about Brock.