The Undertaker/Brock thing at UFC was all the way back in October 2010, though. The Brock/Rock foreshadowing was when Brock was ripping through HHH's office and stopped and stared for a few moments at the Rumble poster in the hallway that had Rock's face on it.
I'm not looking forward to the match either but I'll take it over another Rock/Cena one. By all means, I think WWE would see more dollar signs in Rock/Brock than they would another Rock/Cena bout. I'm hoping Rock misses Mania next year because of Terminator 5, though. Seeing what they do with Brock or Cena (can't see Rock wrestling anyone but these two) without Rock there is interesting.