I'm not going to go into speculating about who Red John is, because I think there are enough clues for almost every person on the list to somehow fit the role. I just wanted to point out that it wouldn't really be much of a feat to get into Patrick's deepest psyche the way Red John apparently did on the last episode. If you'll recall, Jane was in a mental hospital for something like three months after his wife and daughter were murdered by Red John. It doesn't take a huge stretch of the imagination to believe that RJ was either at the hospital during that time, or had someone inside gathering information that he could use later. It seems plausible to think that at some point, Jane tried to return to that particular thought while he was there, in order to cope. Jane said that he never told anyone about that memory, but that doesn't preclude the possibility of him muttering to himself, or even hypnosis. We can say that Jane may be impervious to most attempts at hypnosis, because he is acutely aware of himself and others, but while in the hospital, he was vulnerable at best, and could have been taken advantage of by RJ.
I'd also point out, that even if we ever get to find out who RJ is, I think the more interesting question is why he does it. Everything to this point is mostly speculation: maybe he has a problem with women, maybe he just likes having power over others, maybe he's just a deranged lunatic who gets pleasure from murdering people. I think that after everything is said and done, it will be far more interesting to get a glimpse inside of this guys head, than to just go, "Aha, so he's the one!" and be done with it. I've been pretty happy with how the show has gone thus far, so I think that they will probably deliver a satisfactory conclusion to the Red John saga. Will it go on after Red John? Who knows...
