I ACTUALLY think, that even Scooby-Doo writers are better at explaining things than Heller and his team of geniuses, in Scooby-Doo you could at least figure out yourself who was the bad guy because of all the actual clues, and they always explained everything.
I'm okay with sheriff being Red John, to be honest his identity wasn't that important - what was importatn though, was to tie up all the loose knots, explain everything there is to explain. Why the hell were they giving us all those clues, from season one to six, all the Kristinas, Boscos, "He Is Mar..", Rosalinds...?