I would be disappointed if it is not him. 

There are several reasons, some people here have mentioned.

* The underlying of my reasons is the Wow factor that the show needs! In the end you need to say, wow! that was smart! If Ray Haffner or Stiles or Bertram are RJ, then how on earth in the end you would feel well of showing a detective show for more than 100 episodes?! So I will explain how that Wow factor is built, it it is Patridge!

First 3 simpler reasons,

1- There is too much emphasize on him being dead. And it is not believable. If you think about it, If they wanted to kill any suspect from the list, it is harder to make the show so bad, that the audience still believe he is not alive. 

2- In the Script, if you were RJ, and you're such a smart guy, what would you do after you tell Patrick that you know the list, you'll wait until everyone is dead and let him catch you?!!
Nope! you would fake your death! and enjoy watching the show! That's a classic Red John everyone expects from!

3- All the others are so much visible, so much obvious for being RJ that it is funny to be them. Even if my theory is wrong then the show in not that impressive, you agree when it is giving direct clues that Reede Smith or others are killing people, connecting them to RJ!


** Now the WOW Factor for the show:

- The classic way for proving that we were all wrong and the show's director is so smart, we need a flash back! we'll go to the previous cases, when we see the RJ's opening to the case. The interesting thing about Partridge is that he was there from the very FIRST EPISODE!
He was there and misinforming the police team about a case that he knew it wasn't his job as RED JOHN. But he still did that with confidence, because he knew that Patrick's first job is there and he was there to observe him. To guide him! Because he has always liked Patrick! The fact that he was there and playing such a cruel joke in the first episode, makes a real shocking wow factor when you see it in flash back. You feel that you had been tricked nicely and you'll probably don't feel wasting your time. It also proves another point! That the writer's team has been planning the roles of the characters from the very beginning. And if you look at it well, you would see that he would show up every now and then, and that's what you expect from RJ and more importantly the writers' team.
Not to build RJ's character in the middle of the series! or just bring him for the last episodes.
This is another level of professionalism for the writers and that's how they are satisfied with as well!

Thanks and I hope it is convincing!,
Tayaz


 - 

OK, it should be obvious now why Kirkland was asking the "fake" suspects if they recognized him.  If one of them was actually red john, they would certainly recognize him since they killed his twin.  So we can now eliminate Partridge and Kirkland.  We can eliminate Reede Smith, Sheriff McAlester, and Bertram.  They are part of this new story line about an inside group that will be an ongoing part of the plot after red john is revealed.  

That leaves just Ray Haffner and Bret Stiles.  Haffner is joining the CBI to help with some kind of investigation on next week's episode.  He is the only one that fits the profile to be red john, unless red john turns out to be someone not on the list of 7.

Also, I've always thought the "he is mar" was going to be "he is married to......", but I just never could put the pieces together.

CROKUS9 posted a comment to my THEORY #6535 and made an extremely good point:

"And to add to your theory.. It was a Mexican prostitute who wrote " he is mar" on the wall..If Jared Renfrew told her to write it, he would have said "ellis mars" and to a spanish speaking person, Ellis Mars sounds like "el es mars" which means "he is mars"

Also:  the Mexican prostitute must have written is as she was facing the tile and Renfrew was not in position to have written it.