“Why would God create something so evil and so imperfect?”
Well, if Satan was created with free will, then he wasn’t created evil, or imperfect, unless you consider free will itself to be imperfection. It’s one of the possible consequences of free will that results in the evil, but it’s also one of the consequences that results in good.
Virtue only has meaning when it’s performed without compulsion or self-interest. So, if free will, and the possibility of choosing evil, was removed, then there really wouldn’t be any meaning to the good that we might do. Basically, it would be a universe where nobody ever apologized because they meant it, but always because their Mom and Dad were forcing them to.