only 2 things that occurred to me while I watched the previous seasons:
-The "He is mar" clue, someone already thought that could be "He is Marshall"?  We all know that Red John works on law enforcement, this makes sense, you dont think?
-On Season5 Episode 13 we knew that Red John was a Visualize Member, like Kira Tinsley said to Jane when she has been caught by him, that was a Visualize member that requisited her services.

Thomas McAllistar is not a marshall and never refered as a Visualize member in entire season. Open for your opinnions! Sorry for my bad english