I don't have a theory and I have stopped trying to figure out.

But what IS CLEAR is that, we have 2 groups amongst us fans:

1. Fans who think/want Brett Partridge as Red John
2. Fans who think/want Ray Haffner as Red John

Now, what would be fun is that writers coming up with something that really really surprises us. Someone else who we know.. That'd be awesome.. and healthy for the show too.
Or maybe not so.. Anyway, I am of the Partridge fan group.

To all my fellow Mentalist fans, I'd say

               KEEP CALM
                      AND
                WAIT FOR
 RED JOHN vs. JANE BATTLE!!