I should clarify that season 8 is my second least favourite season of them all (7 is my least favourite). There were issues with pacing (especially in The Last of the Starks), there were problems with a lack of detail that would have made a difference come the end, and I think it could have benefited from being at least 1/2 episodes longer. But I love the show and I loved the final season, so loving something means I can acknowledge its flaws and still take a great deal from it. I feel like I should make it clear that I do have a level of positive bias towards it, mostly because of everything it did for me when I started watching it back in 2015.
But regardless, I think what they did really took guts. It was really bold to decide to go down that route and stick to it. Before the season aired, my preferred ending, as it were, was for the Night King to take Winterfell, to be defeated at King's Landing, and for Cersei to somehow be taken down in the chaos, leaving Jon and/or Daenerys to either take the throne or hand it down to someone else. Looking back, I'm glad I had no say in how things went, because my version of the ending was far too simplistic, far too conventional, and actually betrayed everything the show (and books) originally wanted to explore.
Forgetting the books for a second, the show was always questioning the true nature of power and the human cost of lusting after it. How do people behave when they have power? Do they use it for good or evil? Does it consume them completely? What tactics do they use to hold onto it? If they don't have power, how do they go about seizing it? Are they ever willing to give it up if doing so is for the greater good? Can you rule the land and "break the wheel" at the same time? Can you weigh up your personal demons against your responsibility to be an honourable human? And so on and so forth.
I think the way the show ended considered those questions again after season 7 essentially ignored them (which is why it's my least favourite season). How did Daenerys behave when she finally had ultimate power? Did she use it for good or evil? Did it consume her completely? Could she rule Westeros and "break the wheel" at the same time? Did her personal demons stand up to scrutiny when her responsibility was to be a good person? You get what I mean. Remembering the books for a second, GRRM said that ASOIAF was supposed to be an analysis of "the human heart in conflict with itself".
With that in mind, Daenerys was just a flawed person like any other in this story, as capable of slipping into authoritarian mode as she was capable of slipping into liberal mode, and vice versa. The moment she burned King's Landing to the ground was just one of her many displays of authoritarianism, it just so happened to be her final major act and thus defined her legacy. Trying to read her story as a familiar "progression", as though her arc told the story of someone who went from being a compassionate ruler to someone capable of such villainy in the blink of an eye, wasn't how I took her story in the end.
There's a reason why the description of most Targaryens' nature is constantly related to a coin toss in that popular Westerosi saying - it (and by extension, Dany) can land on any side at any moment because of a range of factors. Ruling and breaking the wheel don't go hand in hand with fairness. The closer she got to seizing the Iron Throne, and the more her ruling Westeros became a possibility, the more paranoid she became about losing it. She made enemies of potential allies and her advisers, she stopped seeing common people and started seeing disloyal subjects. And then she was all alone, on top of that dragon with the world in her hands, hearing the people she wished to rule crying out in fear rather than celebration. How did she wield that power?
There were little details I wish they'd kept in, like the scene they cut from the finale where Bran allows a beetle to walk over his hand and away to safety. In that moment he has ultimate power and chooses not to wield it, he just lets the world carry on as it would have anyway. It's a neat little way of showing that he has no interest in starting a dynasty or controlling the continent with an iron fist, and it also calls back to that scene where Tyrion wonders why his cousin mercilessly smashes beetles when they pose him no harm.
There was loads of other stuff too - how they essentially used Jon to deconstruct the tropes of the "prodigal son" in fantasy storytelling, how they used Jaime to show that characters don't get redemption arcs just because we want them to - but I thought the main beats of the story were all completely dead on and brought the show back around to focusing on what it originally wanted to explore. I think it could have done with a little more breathing room - for example, I think rushing straight into the battle for the Iron Throne immediately after ending the Long Night was a lot for the audience to handle - but it told the story it needed to.
We're currently in an age of politics, especially in America (crucially where D&D are from), where people are looking for lone figures to make huge changes to long-standing systems that will either consume them or break them. It doesn't matter if that's lefties voting for Bernie Sanders, the white underclass voting for Trump, liberals voting for Hilary, nothing will change how those people want it to. Dany's ending is "meet the new boss, same as the old boss" told in the most brutal fashion. It's nihilistic and cruel but I think it was necessary.
I could go on and on and on and on about the final season and explain in even greater detail all the little things I love about it, but I'll just leave you with a line Tyrion says in The Last of the Starks that should explain why the Night King was easier to kill than human greed and the lust for power: "We may have defeated them, but we still have us to contend with."