I read the books and watched the series. I vaguely recall a few times she expressed some regret that her father burned people alive, etc. But she's also adamant that she's queen of Westeros and that's the beginning and end of it. OK Robert started his Rebellion based on a false premise about Lyanna Stark, but the king on the Iron Throne was also mad. The other houses including the Lannisters were mainly in it because Aerys II was mad. Does anyone remember what's the most Daenerys ever said about the Rebellion being her own family's fault. Has she ever mentioned anything about the King Slayer (Jamie Lannister) being justified, or she wants his head or what?
I think the dialog between Barristan and Daenerys when he reveals his identity is telling in this matter:
She turned to Ser Barristan. "You protected my father for many years, fought beside my brother on the Trident, but you abandoned Viserys in his exile and bent your knee to the Usurper instead. Why? And tell it true."
"Some truths are hard to hear. Robert was a . . . a good knight . . . chivalrous, brave . . . he spared my life, and the lives of many others . . . Prince Viserys was only a boy, it would have been years before he was fit to rule, and . . . forgive me, my queen, but you asked for truth . . . even as a child, your brother Viserys oft seemed to be his father's son, in ways that Rhaegar never did."
"His father's son?" Dany frowned. "What does that mean?"
The old knight did not blink. "Your father is called 'the Mad King' in Westeros. Has no one ever told you?"
"Viserys did." The Mad King. "The Usurper called him that, the Usurper and his dogs." The Mad King. "It was a lie."
"Why ask for truth," Ser Barristan said softly, "if you close your ears to it?" He hesitated, then continued. "I told you before that I used a false name so the Lannisters would not know that I'd joined you. That was less than half of it, Your Grace. The truth is, I wanted to watch you for a time before pledging you my sword. To make certain that you were not . . ."
". . . my father's daughter?" If she was not her father's daughter, who was she?
". . . mad," he finished. "But I see no taint in you."
"Taint?" Dany bristled.
"I am no maester to quote history at you, Your Grace. Swords have been my life, not books. But every child knows that the Targaryens have always danced too close to madness. Your father was not the first. King Jaehaerys once told me that madness and greatness are two sides of the same coin. Every time a new Targaryen is born, he said, the gods toss the coin in the air and the world holds its breath to see how it will land."
Jaehaerys. This old man knew my grandfather. The thought gave her pause. Most of what she knew of Westeros had come from her brother, and the rest from Ser Jorah. Ser Barristan would have forgotten more than the two of them had ever known. This man can tell me what I came from. "So I am a coin in the hands of some god, is that what you are saying, ser?"
"No," Ser Barristan replied. "You are the trueborn heir of Westeros. To the end of my days I shall remain your faithful knight, should you find me worthy to bear a sword again. If not, I am content to serve Strong Belwas as his squire."
A Storm of Swords - Daenerys VI, emphasis mine
Her initial reaction here is denial. At this point, she was not aware of what truly happened, using terms like usurper.
From this point on, she becomes more and more aware of what it means to be a dragon. The entire Meereenese plot was designed to emphasize this internal struggle. She wanted to be a good ruler, balanced and stable, but on the other hand, she has Targaryen blood, the blood of the dragon. For an interesting read on this plot, why GRRM struggled so much with writing it and a good analysis on the desire to rule on one side, and the nature to conquer on the other, I definitely recommend reading the Meereenese Blot.
At a later point, on the day of her wedding in Meereen, she has the following conversation with Barristan:
"I want to know. I never knew my father. I want to know everything about him. The good and … the rest."
"As you command." The white knight chose his words with care. "Prince Aerys … as a youth, he was taken with a certain lady of Casterly Rock, a cousin of Tywin Lannister. When she and Tywin wed, your father drank too much wine at the wedding feast and was heard to say that it was a great pity that the lord's right to the first night had been abolished. A drunken jape, no more, but Tywin Lannister was not a man to forget such words, or the … the liberties your father took during the bedding."
A Dance with Dragons - Daenerys VII
At this point, her position has softened a bit. She is interested in her father, but still avoids the word "bad", using "the rest" instead.
A Dance with Dragons ends with Daenerys finding her resolve, deciding that she is a dragon, that her words are "Fire and Blood", that the dragon does not plant trees:
You took Meereen, he told her, yet still you lingered.
"To be a queen."
You are a queen, her bear said. In Westeros.
"It is such a long way," she complained. "I was tired, Jorah. I was weary of war. I wanted to rest, to laugh, to plant trees and see them grow. I am only a young girl."
No. You are the blood of the dragon. The whispering was growing fainter, as if Ser Jorah were falling farther behind. Dragons plant no trees. Remember that. Remember who you are, what you were made to be. Remember your words.
"Fire and Blood," Daenerys told the swaying grass.
A Dance With Dragons, Daenerys X
This suggests at very least that her own claim to the throne is still as strong as ever in her own mind. Admitting the toxic madness of Aerys II as a legitimate reason to remove him from power weakens her own claim. If she (only slightly) justifies the transition of power to the House Baratheon, concedes to her enemies. From that last scene it is clear that she is not ready to do that.
Barristan is the first to truly say it as it is, Aerys was mad. This is met by denial.
During the time in Meereen, Daenerys the denial goes awake, but towards the end of the books, she is not ready to really admit it yet, as we can see from her wording.
In her last scene, she resolves to go to Westeros to take up her claim. This does not go together with legitimizing the rebellion.
We always have to consider the possibility that the Mad King...wasn't actually mad.
In multiple other instances, the "official" story that most people believe is utterly false. Most people believe Ned Stark was a traitor. Most people believe that Tyrion murdered Joffrey. Most people believe Rhaegar kidnapped Lyanna.
In many ways ASOIAF is a story about stories - how and why they're created, how people use them, how they become cemented. There's a story that Aerys was insane - but we don't get to see for ourselves in a direct narrative, so how can we know? Ser Barristan's testimony seems pretty powerful - but the men around a powerful figure can sometimes find their leader's behavior mystifying, because they don't understand their full motivation. The Night Watch mutinied against Jon Snow because they thought he was a traitor and a fool. Was he a traitor and a fool? If not, then the mutineers were simply mistaken - and maybe Ser Barristan and Jaime Lannister were mistaken, also.