At least one person on the WWE creative team has suggested that they not do Rock vs. Cena II at all. The argument is that there are no more one-time-only dream matches, there haven't been any in years and there aren't really any that can be done anytime in the near future - at least dream matches of the magnitude of Cena vs. Rock.
so you got Brock Lesnar, Undertaker, Triple h, The Rock, CM Punk, John Cena .. all competing in one WM and your worry is that there isn't enough starpower magnitude ? lol
any combo of that list would make money, so why waste it on a rerun ?