Personally, I was very upset and displeased with the Red John reveal.  You spent how many years and hours devoted to the Mentalist, only to have this crappy closure about Red John.  I can not for the life of me even imagine that Bruno Heller can honestly say,     "Yep, that sums it up perfectly".  He wrote so well and perfectly the entire series with many hooks and plot twists that this ending seems so hurried, simple, weak and without any flair; not Bruno like.
I admit that I wanted to see the devil himself walk through the door and be this amazing character (Red John) that is the biggest bad you could ever imagine, but alas it didnt happen.  We the fans deserve better than a 10 minute Jane vs Red John ending.  I enjoy reading and watching good shows with quality writing and when crap like this happens it is infact a huge letdown.  My only hope is that this is all a farce and that there is more to come.  Sadly, I know in reality that this is the worst ending we all could have imagined.