Jane said, that he excludes all the possible suspects, that he met only once. Why the hell are McAllister and Smith on the list?
And if he met them again offscreen, it doesen't count. 
I can't acceppt Red John being someone, who should not even bee on this list. 

Great series, but the last seasons were awful. FBI? Can't suspend disbelief on that.
If I were to pick a number one Red John candidate, then it would have to be Rigsby. His father was a biker dirt bag, he fell in love with the redhead, he says things that are out of character, and he is, like someone else said, a classically trained actor. There could be no better choice! 
If one were to watch the episode where he is on an island with the cbi team solving a murder, then one could see how Rigsby could be a great Red John. 

Cause hes always there ;)

I think it’s the forensic guy. He’s small. The person who shot the film makers was small (a woman or a small man). The two people who worked with Red John and later killed where in law enforcement (the deputy sheriff and the secretary). Remember when the secretary was killed Red John cut her with a poison. Someone no one would notice. Red John walk right past the guards and got to the secretary. Someone who could get strange poisons. Someone who knew how to shoot a gun.

I think it had to be the waiter, the voices are similar but so was the detective-after watching it twice already! Can you imagine if it were someone on the cbi squad though? I hope this wasnt one of the many tv series that were cancelled this year!