ok , let me start this off by saying many people probably understood heller wrong when he said the suspect was on the list .. because this is what happened:- "Heller can we trust the list" ...
answer:-"yes we can trust the list" .. you guys know how bruno .. even if the list is fake he can't just say that straight up.. My guess is the list is real but with 1 or 2 extra suspects jane has saved in his mind .."Just incase" now let me get back to "What if red john is on the list" , Let me start excluding suspects using completely logical and reasonable arguments , we know that Red john himself went to sophie miller as Jay roth, Back then Brett stiles was famous and too high profile to risk being identified by sophie miller.. secondly he did break out Lorelei martins out of prison , red john would of never done that unless he wanted that to happen.. which he didn't , Ok so brett stiles out , Brett partridge Assuming he is dead which he probably is.. is out aswell , Leaving 5 people , Kirkland goes down the drain in a heart beat because of the season 3 episode 4 promo.. #1 ..torturing jane for the real list of suspects which red john already has..  , #2. he broke into janes room and stole his info while red john knew the list way before ,, 
Now we have 4 suspects left ,,, Lets try our best to exclude 2 more , Gale bertram first... Gale bertram as the director of CBI is too high profile to walk into Sophie millers office just pretending to be someone else.. secondly he doesnt have the correct physical features and seems like he doesnt have the correct charisma... now we can't really exclude reede smith out of anything but i just  will go with my hunch and say hes too shallow to be red john....

Now we're left with 2 people .. Sherrif thomas mcallister .. 
                                            Raymond haffner

Now the sherrif would make a good red john because of one thing , The actor Xander berkly has been the criminal mastermind of the show nikita and is a very skilled and talented actor and many clues were represented about him in season 6 episode 3 ... "His stealthy movement, the fact that when red john saved jane and came back to scare him he moved quietly.. secondly..  he saved jane on the roof top , could that be a sign , that red john saved his life twice?...  thirdly his pointy shoes .. when rj saved jane from the copy cat killers he was wearing pointy shoes aswell... theres the scene when he freaked out from the pigeons oluaghlin asking van pelt to come to napa county...him whisteling.. etc etc

Haffner also suits because of some clues such as him liking Teresa Lisbon and him being from visualize , having money , being charming and yet creepy at the same time... Also one scene where he asks cho "Who do you think is smarter , me or jane?" cho says definitely jane.. Haffner then has the creepiest smile on and walks away as if thinking if hes smarter he would of caught me by now.... 

Anyways thank you guys for reading this long ass post hope this has helped you out i can keep going on and on and on on possibilities outside the list and interviews with heller and etc etc let me know what you guys think in the comments and  Feel free to ask any questions , thank you and bye bye