Although Harker Rosalind said Roy had straight hair, she left out balding.  It sounded like Red John had a full head of hair.  Vint Molinari has a full head of hair, and he looks six feet tall w/medium build.  I start to doubt her testimony.  I saw evidence that Red John was drinking from the same tea cup that Jane used, while visiting Harker Rosalind.  Harker remained friends with Red John - which leads us nowhere.
     (Dr. Linus Wagner) Truly, if he wanted to get caught as red john he would put the smiley face in the right spot. If he was red john and was doing a killing maybe he thought he would get caught, so he fakes the red john killing - changing his MO. In that same respect, if he got tried for being red john and he wasn't found guilty, he could be exonerated for the murders of Red John; hence, he couldn't be tried as Red John.  The courts would have "slapped" him with all the cases at once.  They could disprove that Red John would kill that way, and leave mark that way.  A copycat Red John killing could happen, while he was in prison.  He could leave the prison, because he is friends with police.  Someone would secretly get him out.  He could then commit a Red John killing.  If he gets off the charges of being Red John, Jane could not kill him as Red John.  Jane would go to prison.  Dr. Linus wagner has Harker to testify that Linus Wagner isnt Roy Taggliaferro, and he is legally not Red John.  Jane wont have leverage with the police, when he kills the real red john.
I avoided Dr. Linus Wagner as Red John, but what do we know about Red John? I know I'm right, and you may disagree - McAllister was Red John. A conspiracy that could last another six seasons is closing the book on the Blake Association. Red John could have been hired by the Blake Association to kill Jane's family. He could be a patsy, someone to take the blame for the obvious mistakes they have made. Blake Association could be the creation of someone other than Sheriff McAllister, since he is just a patsy. Linus Wagner knew about red John (read about red john), yet he couldn't portray him correctly. That scene could have been orchestrated by Red John to see how good Jane really is, to see if he could spot the difference between truth & fiction - not good or evil. Its subtext seems to make a story arc for an antagonist (or anit-hero).