If Game of Thrones (and A Song of Ice and Fire) were going to give you the standard fantasy epic, Robb Stark would have arrived in time to save his father, every single member of the Stark clan would have reunited to take back Winterfell from the Boltons, the Red Viper would have emerged victorious, Theon never would have betrayed his adoptive family, and sniveling weasels like Littlefinger would have been dispatched a hell of a lot sooner. But that's not what we're getting. GRRM has said on many occasions he wanted to take your expectations and turn them on its ear. And he did just that. So while there is a very strong argument that the showrunners' headlong rush to reach an epic ending has not been executed well, it is at least in line thematically with GRRM's aim with his tales.
As someone else on Twitter pointed out, the Cleganebowl was almost pathetic, because that's exactly what it was--two broken and scarred men selfishly fighting to the death, knowing there really wasn't any real victor no matter what the outcome. The Hound even laughs, acknowledging the pointlessness of it all. The one lasting legacy he left was warning Arya not to become him.
I kinda hoped Yara or Theon would have had a chance to drive an axe right through Euron's head, but I like the way Theon went out, and Euron's end, though also rather anti-climactic, kinda made sense. And yes, it makes sense Jaime, even with one hand could take a Euron who had just emerged from the sea and was completely exhausted after having to swim to shore. That wasn't some gallant swordfight, it was a brawl, and Jaime even used his metal prosthetic as a weapon when he bashed in Euron's throat with it.
As for Dany, the show gave us exactly what we all wanted...or what we THOUGHT we wanted. Cersei dying at the hands of Daenerys Targaryen. But they did it in a way that horrified us, and really, the concept is brilliant even if the execution wasn't. Dany really isn't that much better than Cersei or Robert, or even Joffrey. She said she wants to "break the wheel" but that's a load of bull****, she just wants the wheel to stop at her. There was nothing she really offered that her predecessors didn't, except a very fiery form of execution for any who dare cross her. Quite fitting that she ended up igniting all the stores of Wildfire her father had hidden away in parts of King's Landing. Again, her fall from grace was abrupt, but it wasn't from out of nowhere. She made a fatal mistake making the big cross from Essos. She could have ruled over that entire continent for the rest of her life and been happy. She may technically be from Westeros, but she's just as foreign to the people there as the Dothraki.
In the end, the only person in Westeros still alive with even a lick of common sense is the woman who started out as a superficial, preening little girl trying to win the favor of a handsome prince and/or knight, neither of whom wanted anything to do with her.
I did really like the fact that they somehow did the impossible, gave us Cersei and Jaime's end in a way that made them sympathetic, even after all the horrid, awful things those two horrid, awful people had done. Kudos to both actors for giving us that.