alright I could be wrong here, but it is just a thought, Since the eigth episode is called "Red John" and based on the promo we have seen for the episode this upcoming sunday... I say it is quite possible that red john is revealed at the end of this episode on sunday night.  The following episode will show exactly how he operated all these years and answer the questions we need answers too.

It explains why past actors are back in the red john episode (flashbacks)  and the episode description says patrick comes face to face  with red john .... it does not say we don't know who he is beforehand.......

anyway just a thought....