We inevitably get to the point where, though there are oodles of episodes left, it starts going “jump the shark”. For me, it was when it started going too graphic, actually showing the murders happen in detail (Series 2), grittier, less “fun”. Plus the badly treated gf was starting to wane as a drawcard … even Jacoby was now and then left out.
The issue for the redactor, moi, is it starts to involve more sifting, longer episode watching to rate it worthy of you … for example, there are three series 3s I’ve just gone through, none were up to it. Shall keep looking for now but it’s taking longer and longer if you get the drift.