Let's think on this one long and hard for a minute.

First, pre-supposing that the episode that is leaked IS the real episode.

If that's true then we must keep the following things in mind:

1. The Mentalist is a police procedural show that appears on CBS, the same network that brings us the CSI, NCIS, Criminal Minds, etc. I would hardly call any of their episode's crescendos shocking or clever. Just amusing, somewhat.
2. The Mentalist is not like Castle, where there are twists and turns, followed by twists and turns, and the final whodunit is the both the first and last person we'd suspect. Castle is much lighter, whereas the Mentalist is very dark. Jane's obsession/hurt over his family's brutal murder haunts and colors everything he does and experiences.
3. Every Mentalist episode usually boils down to Patrick knowing slight ahead of time the who/how dunnit because there is usually ONE thing he deduces before anyone else. In Red John, it was the explosions, the bombing was "theater" and Brett Partridge's having been part of Blake and switching out the Sheriff's DNA. Although not specifically addressed in the Red John episode, Patrick must have known that Sheriff was lying in the house when he denied being Red John, because of what he said about needing to look Smith and Bertram in the eye in the next episode.
If you were to watch it back again, over and over, you'd see that the episode in itself isn't bad. It's actually quite good, poetic. But when you relate it to all the other seasons and episodes, very few things "connect." I think this way, Heller can move Jane's character past his loss, Red John, and forward to Jane doing what Jane does best, being completely emotionally detached from the cases he consults on and solving them faster and better than anyone else.

I'm also wondering if any of us here, who are true fans of the show and its characters could have been satisfied by any ending. You think it's possible that Heller purposely made a mediocre, melodramatic Red John finale on purpose, just because the expectations could not possibly have been lived up to?

A minority, but perhaps plurality, of voters are relieved it isn't Partridge. But even some Sheriff voters are disappointed at the hum drum ness of it all. Obviously the lead up to the reveal was more satisfying than the reveal itself. Maybe it was meant to be.