I would say it's flawed in that it's not as good as the first film, and the animation quality is a bit weaker.
However, it's still a pretty good movie that explores the aftermath of Scar's rule and how it affected everyone, even after the Pride Lands recover.
It absolutely makes sense that Simba turns out that way, not just because Scar killed his father, but Simba used to admire him.
He would listen to him and take any advice Scar would give him, partly because Simba saw him as the cool uncle who would let him do whatever he wanted, regardless of whether it put him in danger. And though Scar never cared about Simba, we can see that from their interactions. He still managed to exploit his nephew's admiration for him and used him in his plans to kill Simba and his own brother.
https://youtube.com/watch?v=6KlL8AWa_DM
It makes sense that Simba would become overprotective of his daughter to avoid repeating his mistake, especially after the incident with his own father, to the point that he didn't trust Kiara to hunt on her own, even when she was an adult.
https://youtube.com/watch?v=Ambjdj4MMZA