it was a fan serviced season.
There's been prevalent fan service since Season 4, and it completely swallowed the show after it. Take any Cersei scene in Season 2 and put it next to any scene of hers after Season 4. The writing has been terrible and fine, talented actors have been wasted. There's been generally much less nuance, finesse, message, and art after 4, which is a very bad thing considering the show as a whole has squandered the universe it has been given, and crafted what is now its long-running recurring theme of: life is horrible and cruel, there is no purpose, and there is no God (and if there is a god, he hates everyone). It hasn't just mistreated its source material (with characters missing and and plot points never fitted in); it has utterly defiled the source material.
Here's just a couple things that did not sit well with me:
Brienne getting put into a situation in which she was able to find Stannis and kill him (in Season 5),
Ramseys getting put into a situation where he is imprisoned and killed by his dogs while Sansa watches (in Season 6); it all happened too perfectly for me to remain immersed; they were plot points that were too clean that yielded absolutely nothing for the narrative. We should gain no satisfaction from conventional resolutions, but find it in unexpected places through interesting means.
Edit: I should have given an example as to what I meant by satisfaction from unexpected places. Joffrey being killed by Olenna when it was Robb Stark's revenge to take. It was completely unpredictable and out of place for the narrative. But it made complete sense when it was explained and it didn't feed into the idea of this fan service perfect justice/revenge plot.
I just have the feeling that season 8 will just ruin my experience and I'll have to put asside my purist side again to be able to somewhat enjoy this series finale.
I've forced myself to watch the show because I'd rather watch plot points unfold on TV than discover spoilers on the internet [or from yappy friends] about said plot points. We're really getting forced into this predicament.
I don't see any other viable option they could have went with. Putting the show on hiatus until they gain the source material would have been my wish, but with GoT being their golden goose, they would have milked the show dry until we were down to the marrow. And I think it's the showrunners who want to end it at Season 8. If it were up to HBO, we'd probably be getting more seasons than we could stomach.
But like you said , I would not be surprised if Martin is gonna do last minute change to his book. Anyway he said himself if I remember correctly that a lot of stuff would not play out the same way that the show. (A little bit reassuring to be honest).
I don't think George is going to change a single thing about the book. He said that some people have pieced together things in the books (many have theories, but only few have gotten it spot on) and he's said something along the lines of not changing the book 'just because someone has figured it out'.