i think the problem is that they definitely did steps 1-7. But they missed out on steps 8 and 9 and went straight to 10. Dany didn't do something morally questionable prior to this so it falls flat for some. Again a casualty to the shorter episode length. I think if they showed the journey to King's Landing, with them stopping over at, I don't know, the Riverlands and Dany demanding piety while also claiming to be a liberator and ending up burning people who don't bend the knee - not soldiers, not lords, but civilians - it would be that "oh shit" moment that would have led to proper build up. Instead, they teleported around the map and the character development suffered.
Because right now a lot of people saying this is out of character are saying her past kills are justified. She needs that one morally questionable kill before the big bang. To me, that morally questionable kill is burning the Tarley's. But many of her defenders consider that justified between they wouldn't bend the knee during wartime.