Descendants: A Lost Revenge
I personally didn't care for it. I wish it were more about Uma's legacy as a sea witch, not the whole pirate stuff, especially when it deals more with Harry's family, and he pretty much gets sidelined. Also, the Sea Witches were Sirens and not sea witches like Ursula. I don't know why the writers called them sea witches. Neither in mythology nor in Disney are sirens, sea witches.
I think a better story would have been Uma's struggle to live up to her mother's expectations and to others' expectations for her because of her role in bringing the barrier down. On one end, you have Ursula expecting Uma to carry on the legacy of being a sea witch, but on the other end, you have Mal and co. expecting Uma to be a leader to the people of the Isle and a good example. So the story involves Mal/Ben offering Uma the position of headmistress of Auradon, while Ursula also offers to teach Uma to tap into her sea witch powers. Both offer powers in different ways, and both are compelling to her, but she can only really choose one. If she learned to be a sea witch with Ursula, it offers her the ability to learn the magic she was denied due to the barrier, along with the freedom to explore the seven seas and all the treasures they hold. She also gets to bond with her mother. On the other hand, being headmistress means she can change the rules that were once used to oppress her and others like her.
This is just my opinion.


















