Plot holes aside (terrible editing, perhaps even writing)- the final showdown with Red John was actually smart. It is a relief to see a show bucking the trend (read: torrent) of anti-hero veneration. Yes, the attractive, sickeningly interesting antagonist is interesting as a change, not as the norm. The exposure of Red John as a "mortal-after-all", played very well by X.B., was more than I could ask for. Personally, having followed the show since Day 1, I kinda expected a big, mindless, mythology-based finale- Deathly Hallows Part II style, and, after watching the ep. for the second time, am weirdly glad I didn't get that.  
HOWEVER: Plot Holes and weak writing. The whole season (and esp. this episode up until halfway through), came across as forced. Like many on this site, I think the RJ storyline should've ended with Carter. Since that hasn't happened, oh well- I guess The Mentalist has to move on. The diff. is, back then, they did not explain much, but the clever build-up of the finale more than made up for the "out-of-the-blue" RJ. Here, a terrific showdown, were RJ is finally downed by his ego (and Jane's simple thinking, ironically) and the brilliant X.B. and Baker, are all smudged by a terrible build-up. 

So, while I was happy with the conclusion, the episode as a whole was let down by the bad build-up, plot-holes, leaks and etc. I am however looking forward to the RJ-free Mentalist, since Heller and co. don't have a convoluted, drawn out plot to satisfy now. Hopefully they won't create another one right away. 

As for those hating the episode for making RJ come across as weak- well then. The Mentalist= PJ, the protagonist, hero of this tale. RJ was supposed to be exposed as pathetic (as all villains are). That's Patrick's triumph over RJ- reducing him to a terrified mortal like himself. I believe you have all fallen into the trap of RJ-worship, while what we should have been anticipating (from the hyperbolic build-up I despised) was RJ being stripped of his mask and halo, down to his flesh- and he's an old-fashioned criminal, no nuancing or grey-areas. And that was refreshing to me, and disappointing to those who believed in a Heath Ledger style Joker kind of RJ. This is the ultimate disappointment Heller talked about: criminals are just that: puny humans with over-sized egos and undersized balls. If you don't like the philosophy of the show's creator, maybe you shouldn't watch.