My guess at why Red John reveals himself. Pure guess, nothing more... or is it? No, I assure you..its a .....guess. Hehe.

Patrick played Red John from season 5 episode 8, to season 6 episode 8. He knew who Red John was before he ever made the list. The list was to destroy Tyger Tyger (RJ was leader of law-enforcement conspiracy) and Visualize's ties to Red John. During Patrick's pursuit of Tyger and Visualize he's very cold with Brett Partridge, who he meets 3 times. But he doesn't kill him, even though he knows he is Red John.

Eventually Red John who has lost everything meets Patrick in the park, after Patrick announces Gale Bertram is Red John. He lost to the better man, but for some reason he thinks Jane won't kill him because Jane refrained all the other times they met.
Anyway Patrick physically overpowers him very easily and its a damn smooth, emotional scene. In flashbacks, all the "cool tricks" Red John did to be ahead for all seasons was actually due to Ray Haffner's surveillance prowess. So the mastermind is pretty much Ray Haffner. But the creepy killer with resources, who wanted to mess with Jane was Partridge. That's how I see it.Pure guess of course.