It seems to me that Ray Haffner is Red John, but I like the idea that Mahoney put out about RJ being a forerunner to something bigger. Could this Great Red Dragon be Tyger Tyger? Is RJ an agent of TT? If that were the case then I see a much bigger narrative enfolding than just who is Red John? That would make for a better season, and better conclusion to the series itself. This is about to get real interesting. 

As for people's insistence that Haffner can't be RJ because of his behavior in 6x05, I think that does more to confirm his being RJ since it has become obvious that RJ is behind Jane which is different from the past. RJ now does not know what to do since he is behind. He is getting sloppy because Jane is finally about to get him.