I haven’t seen the original Sleeping Beauty in years. I really don’t remember much about it, outside of an attractive girl put to sleep by a curse that could only be awaken by a kiss. I vaguely remembered a dragon and some other things as well, so when I walked into Maleficent I walked into this story mostly blind, and I enjoyed the heck out of it.
In the original Sleeping Beauty they never really gave you a good reason as to why the Maleficent was evil. She just seemed evil for the sake of being evil. The best villains in my opinion have a backstory and a valid reason for why they do what they have done. There are two sides to every tale, and Maleficent tells the other side of story.