The story of Red John is over. Look at the episode titles. Every episode up to this one has a title with something to do with the colour red but now the episodes are titled so that the colour Red is not mentioned. this tells me that the show is moving on from Red John.
This show is all about Red John. The show became so popular because of Red John. Without Red John its just another cop drama. Red John is the reason why we are all on this website. Thats why I think the writers will give the fan what we want which is Brett Partridge. So I think Partridge will come back somehow and turn out to be RED JOHN!
I personally think Red John is a group of people; not just 1 person. I do think there is a leader who could be Bret Stiles. A rich man who knows how to control people should be Red John.