I'll echo what has been said earlier, it went rapidly downhill after David Morrissey left after S4. What became clear is that they had no intention of telling a story and were happy to recycle the same formula over and over again, defeat baddie, find new settlement, all appears fine, but you know it isn't, big fight, wash rinse repeat.
Then a short while after DM leaves we have the Glenn jumps the shark debacle. I did watch a little longer but my initial reaction was to immediately switch it off, and it's not often your gut instincts let you down.
Overall, a 6/10 from me, and really a poor investment of time after S4.