I think the end of Red John was just irrelevant, firstly from what fans
were expecting and secondly from the clues they provided over the
years.

I also believe that Bruno Heller just wanted Red John to be a character that
no one could ever explain how he would be RJ.So the clues don't add up,
therefore there will be no flashbacks.
In addition, to me it seems that
Jane tries to forget everything about RJ and what happened the previous
10 years.So another clue that there will be no flashbacks (except of a
possible RJ return.)

Is Red John really dead?Is McAllister Red John?Is 6x08 the last Red John episode we will ever have the chance to watch?Will they ignore the fact that we need answers/flashbacks etc.?Certainly hope not.

I'm just clueless about a possible RJ return, so I'm not that optimistic.