while there's lots of "evidence" that we "know", the only thing that we truly know is that Red John employs a seemingly endless supply of disciples to carry out much of what he needs done. Is it too far a stretch to assume that the men that Rosalind Harker and Jane's psychiatrist weren't actually Red John either?
Red John's disciples have also proven to be willing to sacrifice themselves for him - carrying out his orders even though those orders will likely get them killed or caught (or require them to kill themselves). Sounds kind of like extreme religious devotion... cult-like devotion. As Bret Stiles already runs a cult, it kinda seems to be the most logical conclusion that he would be Red John. A cult leader that inspires cult-like devotion; wouldn't that fit the bill of being a disappointment (as per Bruno Heller's suggestion about who RJ turns out to be) being that it's a fairly obvious connection?
We now know that Red John does in fact have a network of disciples throughout law enforcement; but was that really all that hard to believe? We've seen people acting on behalf of Red John within CBI all along. In Red All Over (a telling title?) we saw a cop on the scene tamper with evidence that connected a murder to Visualize - perhaps a coincidence, but it could also be a bit of foreshadowing in suggesting that Stiles' organization has followers everywhere (just like RJ).
We also know that Kirkland's brother got help from Red John to kick his drinking and such, which is kind of the type of thing that Visualize does.
On a practical level, I just can't see Red John, a criminal mastermind of this huge organization of disciples (and that's only counting the ones that we've seen), having a day job. Stiles has more control over his schedule than any of the other suspects. The rest all have to punch a clock, so to speak. They have responsibilities that would be hard to avoid if need be, whereas Stiles is at the top of an organization with many loyal followers under him; he can literally set his own agenda and do what he wants, when he wants. He also has more than enough resources at his disposal to carry out whatever plan he might wish to execute.
On a personal level, if I were the creator of a series that was built around one man's search for revenge against an incredibly smart and resourceful, yet utterly diabolical killer, I'd really love for that killer to be played by the guy from Clockwork Orange. That really does seem like a great option if you have it. Just saying.
