Even if the entire "Cassandra is Gothel's daughter" storyline leaded to the weakest and rushed arc of RTA imho, Disney really broke a lot of walls there. For the first time Disney gave us an abusive BIOLOGICAL parent who doesn't love her child and doesn't redeem herself in any way. The closer thing we had until this moment was the deadbeat father of Jim in Treasure Planet, and we don't really know enough about him, we just can suppose he left because he chose adventure to family, but who knows. It's cool for Disney finally admitted even biological parents can be assholes, not only uncles and stepmothers. (And yeah, in the various sequels of Cinderella we see Tremaine being a bad mother even for Anastasia, but Gothel seems more powerful because she isn't just generically a villain who happened to be a mother, she is a villain as a mother).