I think I found out what was so important in the season premiere. Let's base in the fact that there's no punctual reason why red john would want to reveal himself to Jane.

Given this, there's a contradiction between RJ saying Tyger tyger to Jane in S2 finale, considering it like a clue to RJ's identity. Why would he gave up a clue about himself? This is confirmed by Pattridge spelling the same words to Lisbon when he's dying. Why would he reveal those words if they were a clue to RJ?

If Pattridge was a RJ follower he'd have died willingly, because we know he demands sacrifice, and no point in saying a word. If he was treasoned by RJ, he would have speaked the plain name. If he wasn't a follower then why would he say Tyger tyger? And even more, why to Lisbon, who is a direct phone to Jane?

Would RJ want that? Maybe. But this is what I think. Tyger Tyger is a code (as we already know) for a certain mafia within california law enforcement. A very extended net of "cooperation" between the cops. It's a secret organisation, ofc. And a lot of cops take part on it, this is why Pattridge thought Lisbon was part of it and said the password to her.

Bertam, Smith and Mccalister are part of that organisation, therefore their concern about how much "does Jane know", and given that Kirkland started to unwrap the secret, he had to be eliminated. None of this three is red John. considering the three of them are in the "tyger tyger" net, the treat between them in the office was very horizontal.

Had one of them been Red John, the other two would have looked up to him to see what was next. But this behaviour didn't take place in that scene.

So, out of 5 remaining (accepting is one of the original 7 listed), thee have been taken down. Leaving us with Haffner and Styles. I think between those two it's a pretty arbitrary yet obvious choice.

However, let me also point this out. In S2, Red John was giving Jane a clue about this secret organisation, maybe if that mafia fell he would have been the next in the list to run the CBI?

I don't know, I think this theory could be pull even further with more ellaboration, so give it some thought