This is a well done video laying out the case for Dany's turn being badly written. The point isn't that it wasn't hinted that this could be a possible outcome. The point is that the writing to get from point A to point B was rushed, contrived, and executed terribly.
It's funny to witness #teamdaenerys go from "she's always been a good person" to "well ok, maybe she had some bad character flaws, but her descent into madness was rushed". It's like you guys are going through some Kubler-Ross grieving cycle.
"Foreshadowing is not character development", I've seen that nonsensical catchphrase cropping up more and more in the context of this episode and now suddenly every youtube monkey is copying that in order to use it as a cornerstone for their high-browed media "critique". What's it even supposed to mean? Foreshadowing is a way of telling people about the potential downfalls of a character. It's a way to let the audience know what hidden flaws they might find behind the facade which might lead to the characters ultimate undoing. If anything, it's a narrative device to be consistent with future plot points and to prepare the audience for the upcoming revelation.
Was it "bad writing" when Michael Douglas went berserk because he wasn't allowed to order his frikkin' breakfast menu at Whammyburger? Was Peter Finch's "mad as hell" scene badly written when he went full ham on his audience as a news anchor? Was it "bad writing" when Daniel Day-Lewis reduced Paul Dano to a bloody pulp with a bowling pin? Was Martin Sheen's meltdown in Apocalypse Now badly written too? What about Tom Cruise in Magnolia, Robert de Niro in Raging Bull, Stallone in Rambo, Bale in American Psycho, Nicholson in The Shining...?
Even in real life, people go frikkin' mad for much less because civility is oftentimes just a flimsy sheen, a fragile veneer that is covering the endless abyss of madness. There is no "safe" descent into madness and there certainly is no "one true way" to go down in flames, be it slow or fast. There is no rhyme or reason, no standard procedure, it's frikkin' madness. Sometimes it's just the straw that breaks the camel's back.
The people complaining that Daenery's descent into madness was rushed and therefore bad writing are just salty because they didn't understand the core message of the story and because they are disappointed that their beloved
slay queen ultimately failed to claim the throne. They fail to realize that emotionally, mentally and morally bankrupting yourself is the price to pay to have a shot at playing the game of thrones.