If you’re going to make a “from the villain’s point-of-view” retelling of a story, it seems to me that you should aim for something more nuanced than simply making someone else the villain.
If you’re going to make “from the villain’s point-of-view” and simply make someone else the villain, you should make that villain at least as believable as the original villain in the original story. (Honestly, I haven’t seen the Disney Sleeping Beauty in ages—if at all, but I thought the dark fairy in the original tale was a perfectly believable villain. You know...as far as fairies go.)
I hate it when the villain accidentally dies. Let the hero either decide to kill them or decide to let them live and deal with that. An accidental death is a storytelling cop-out.
(That said, I really enjoyed Maleficent. I wouldn’t criticize if I didn’t care. I especially like the twist on “true love’s kiss”.)