There is no way that RAW next week will be the highest rating ever. They are not going to jump from the low 3's to the low 8's in one week, regardless of what is going on and who does or does not appear. However, I can see 2/21/11 being their highest rating in a really long time, moving over the 4.0 threshold, and if they play their cards right, they can sustain this on the road to wrestlemania.
You have to think that Cena must respond to the Rock in some capacity, even if the Rock is not actually there, which he probably won't be. I don't want to be guilty of jumping to conclusions or reading things which are not actually there, but I really do finally believe that this could be the long speculated John Cena heel turn. After being the face of the company for years, single handedly stopping the original Nexus (kayfabe), etc., he will get booed and they are going to chant the Rock's name when Cena enters the ring. I think we can see Cena gradually get pissed off by the lack of loyalty of the fans and have him undergo a short term heel turn.
The Miz will have to respond to the Rock as well, won't he? Plus, we will have to get some sense of direction of who is doing what at wrestlemania. Are the Rock and Cena going to face off in the ring. If so, what happens to the Miz? A lot of unanswered questions, not to mention the continuation of the ongoing story lines.
Call me naive, but I still have not given up on a Sting/Undertaker program either. With each subsequent vignette, I feel more and more convinced that we will see this too. While the vignette eliminated all doubt that Taker is involved, it did not dispel the possibility of a second mystery person, in fact it made it look more likely than ever to me. Add the possibility of this to everything else above ( and we haven't even discussed Triple H, Awesome Kong, or even the possible mystery woman who exited the limo (although personally I don't see a story here, I think that was just to dupe the fans about the Rock, which worked really well if you read through last night's LD), and we have an epic show to look forward to next week.
And just think, a week or so ago, people were concerned about a lackluster show for WM27.