I've kept up with many of the theories on here, with some discrediting others and some interpreting show clues and actor interviews.  I think I have seen valid arguments against each of the 7 suspects being Red John. Taking that into account, I have a feeling that most people are going to be let down.  Personally, if Red John is not Partridge, Bertram or Stiles, I'm going to be very underwhelmed.  How are the creators possibly going to convince us that one of these 7 men is a deeply evil, charming, nearly infallible genius?  Is it going to be satisfying to have someone simply revealed as Red John, and then have him be killed?  Aren't you going to be curious how he pulled off any and all of his crimes?  How he maintained his cover, attracted a legion of loyal followers, turned someone into a vegetable, and outsmarted Patrick at every turn? Do you think this is all going to be addressed?  I sure hope so.

SPOILERS concerning the show LOST below...
To me this reveal is reminiscent of the final season of LOST.  All that buildup, all those questions, and all the fans wondering how it would all tie together.  The big surprise - almost nothing tied together.  No explanations for anything.  Thanks a lot, Abrams and Lindelof.  Huge disappointment.

Don't get me wrong, I love this show, and I've been watching religiously since the very beginning.  I sincerely hope Bruno Heller has pulled off a masterpiece here, but my expectations are low.