After losing Jorah, Rhaegal, and Viserion, and with Jon pulling away from her, Dany no longer has anyone around her she really trusts (except maybe Grey Worm, who will be burdened by his own grief). The show has repeatedly implied that without wise counsel, Dany will go full Targaryen and rain down fire and blood.
Here's the thing: While they have dropped several hints about this, as I have outlined above, those hints have been buried under an overarching narrative of Dany being portrayed as heroic and good. In hindsight, this seems to have been purely to make her downfall all the more tragic. The problem is the last two seasons have felt so rushed that, despite the foreshadowing, there aren't really solid or satisfactory reasons Dany would deteriorate so rapidly.
Time and again she has shown herself to be motivated by good intentions; she has been reasonable and has listened to her advisors — and when she hasn't listened to them, in most instances, she's turned out to be right. She's outsmarted so many others and always fought to protect the innocent.
Every time she's mentioned destroying her enemies, it's been framed as a sign of her strength. Whenever she burned those enemies alive, it's been seen as a triumphant moment — at least until she set foot in Westeros. It wasn't until the Tarlys were executed that Dany's actions were cast as horrific rather than awesome. Aside from everything else, it's not a good look that the show expected us to suddenly believe Dany was becoming a Mad Queen because she was killing white people instead of brown people for a change.
Game of Thrones is trying to have it both ways — to have Dany be a hero and a villain, when her behavior in each instance has (so far) not been markedly different. Moreover, those who are remaining "heroes" aren't exactly any better than her. Jon has killed people for not obeying his orders. The first time we met Ned Stark, he was executing a boy for running away from the Night's Watch. Arya Stark, the "hero of Winterfell," is a mass murderer.
It's not fair of the show to ask us to cheer for one character's bloodlust and vengeance while condemning another. But the way things are looking right now, it definitely seems like they will.