This will go down as one of the worst episodes of television history. You may be tempted to say what sensational ******** but just wait and watch.
Initial reactions have been overwhelmingly negative. You cannot satisfy everyone nor should you try but you have to earn a narrative with proper setup, time, explanation, motive, etc all of which were not on display here.
Daenerys performed the act she did not because of any traumas or betrayals she had went through but because the of the forced narrative and character assassination the writers decided to perform.
She as of this episode is the most powerful person in the world of Game Of Thrones. She just achieved her ultimate goal of taking back her kingdom that like it or not was built by and stolen from her ancestors. For all intents and purposes she had won and obtained all she had ever wanted. She then destroys her families century old Kingdom for what reason!?
If you wanted to portray her as a mad queen then have her constantly afraid of assassins in wait all around her in her own kingdom,encampment, entourage. Have her blaming this person for treachery and executing them without proof. You wanna say the betrayals and loss she has suffered broke her, hell she lost her country shortly around the time of her birth, was sold by her brother, raped by her husband, and still for 7 seasons was vastly a wise and compassionate ruler. Keep in mind she is a hot blooded Targaryen 20 yr old with dragons so she is definitely going to be ruthless and make mistakes at times, but mass murder and destruction of your own kingdom in 1 day... Nah that is piss poor writing at best and character assassination at worst.