The first few seasons were awesome. What else like that has ever been on TV, on that scale, with all the violence and tiddies you could ask for?
Unfortunately, they ran out of source material. George R. R. Martin was taking forever to write the next book, so they sort of stalled for a couple of seasons. I really, REALLY hated the Aya "Faceless Man" and Ramsay Bolton storylines that dragged on far longer than necessary. It seemed like they were just stalling for time. Then they made the final two seasons shorter, and really put everything in FAST-FORWARD. So you had episodes where almost nothing happened, and then suddenly they squeezed huge epic battles into 30 minutes. I have to say this, the Night King wasn't a great military leader, considering his massive, unstoppable army had only one Death Star-sized weakness...