The biggest mistake the show made IMO was creating Cersei as a fairly competent villain and then doing almost nothing with her. Night King rise and swift fall was next. The first half of this season should have been Cersei, the second half, Dany.

Overall, I was hugely disappointed in this season, it was a different tone and focus than the first 5-6 seasons. Given that, I thought the end was OK last night:

1.) Why did the dragon respond to Dany's death by melting the Iron Throne? The dragon isn't going to know what that hunk of metal is for, nor is it going to make a symbolic gesture, because it's just a brainless reptile. That's just dumb.

Two things. First, there is no reason to believe it is a brainless reptile. It recognized Dany. It also recognized Jon as a Targaryen. Apparently by smell, somehow. It also knew when Dany was killed. So clearly dragons have a mystical connection to at least some people. And in a lot of fantasy stories, dragons are actually very wise (though also very old, and these were very young). Anyway, I wondered if the dragon recognized the object of Dany's lust for power on a basic level, and also couldn't kill Jon, so it lashed out at the throne. yes, there is a bit of convenience there, but I can go with it on a show like this.

2.) Jon killing Dany: Dany, new queen of the seven realms, is wandering around completely unguarded? That's just dumb.

Jon was essentially Dany's consort. As far as we know, Gray Worm and her guards don't know of the pending conflicting claims to the throne. Even a dragon let Jon by. I also can see how he would be allowed in without a guard present.

3.) Bran? He's a space cadet that no one can relate to, and he's not even living in the real world anymore. That's just dumb.

Yes, this was silly. Or rather, it could have been OK with more development of Bran, which was badly lacking. Also, I'm pretty sure the actor's blandness contributed to it.

4.) After Dany torched the city, it isn't going to be calm and quiet, with just a few tiny fires burning here and there. Portions of the city should be completely ablaze, and the wounded and injured would be lying around screaming in agony. There would be a constant din of human agony, not a nice quiet scene for characters to do slow walks through. That's just dumb.

Depends on where you were and how many people were killed, IMO. Jon and Tyrion did pass survivors. But there weren't many. There may not have been many. That feeds into Dany's stor yline and fall into madness.

5.) Hello, Jon is the truth heir to the throne. But .... let's send him to Castle Black. That's just dumb.

He had to go somewhere to satisfy Gray Worm. I think the bigger fail was Gray Worm accepting the solution. For all GW knew, Jon would be back in KL in a month.

They should have shown GW finally having his own doubts about Dany's actions. That would have helped a lot with the aftermath.