Over 6 seasons, there are two important things we learned about Red John that I want to focus on.  1) He has a connection to law enforcement or government.  So either he is a law enforcement agent, politician, judge etc or just a powerful figure who can pull a lot of strings.  2) His "disciples" demonstrate an unwavering loyalty to him.  They will do anything and everything for him.  This resembles fanatical or cult-like behavior.  Sure sounds like Visualize to me.
The Blake Association is not a cult.  It is about covering up crimes.  There is no belief system, just pure corruption.  Visualize is more spiritual/religious.  It talks about self-help, change, a new life etc.  Red John's followers (such as Rebecca Anderson, Lorelei Martins, Sheriff Hardy, Timothy Carter) are more similar to Visualize members than Blake Association members.  So Red John sounds more like a Visualize leader a BA leader.  Not so fast, I am not accusing Bret Stiles.  I am accusing Ray Haffner.

Bob Kirkland: works in homeland security.  didn't act like an RJ follower when he died.
Brett Partridge: works with many people in law enforcement and government.  was a member of the   BA.  seemed afraid to die, unlike RJ followers.
Gale Bertram: knows countless people in law enforcement and government.  was a member of the BA.  didn't act like an RJ follower when he died.
Reede Smith: fbi, member of the BA.  he spoke openly with law enforcement, something RJ followers don't typically do. imprisoned, again, RJ followers are killed are broken out of prison before long. 
Bret Stiles: visualize leader.  He calls Red John a "perfectly unpleasant sort of fellow.”  Lorelei's "surprised they didn't become lifelong friends" statement doesn't fit with Stiles.  Jane and Stiles help each other and are the most friendly toward each other than any of the other suspects.  Bret also said, "I know more than you or RJ will ever know."  That sentence makes the most sense if Haffner were Red John.
Thomas McAllister: sheriff, member of the ba.  didn't act like a RJ follower when he died.  the things he talked about with Patrick in the chapel don't resemble any past conversations Patrick had with Red John. 
Ray Haffner: former agent of the CBI, visualize member.

Haffner is the only one from the 7 who has a clear law enforcement and visualize connection.  I feel like he never really believed Visualize teachings, but instead used some of them to manipulate people.  He saw how Bret Stiles had power over people and he joined Visualize so he could learn to have the control.  He was pissed that Jane had more power over Lisbon's feelings than he did.  He is offended easily like Red John.  That's why I think he is RJ.