If anything, they’ve shown she had this tendency for a while. Those who did not see it did not want to see it.
- why was introducing wholesale slaughter in Mereen and Astapur a good idea? It killed a lot of people. Did it solve anything?
- Did everybody forget she’s been wanting to sack and burn King’s Landing since she got to Westeros and it was only Tyrion and her other advisors who were restraining her?
- remember when she burned the Tarley’s AFTER they had surrendered? Why was that necessary?
Clearly some viewers just wanted to hero worship. They wanted a flawless savior. Well guess what. You’re in the same position as the Germans in 1939. It turns out your savior is a bloodthirsty megalomaniac and it’s too late to remove her. Now you’re stuck.
If anything, I thought it a great twist to the story and one that had been set up for quite a while.
Yes, she wanted to destroy King's Landing from the get-go.
The Tarleys would not swear loyalty to Daenerys and said they would stay loyal to Cersei ("we already have a queen"). They either needed to die or go to prison, but could not be let loose to do more mischief for Cersei.
Daenerys has never been flawless, but up to now she was portrayed as "more sinned against than sinning".
You nailed it. Good job.