If it were possible to watch episodes 1-3ish, then episodes 9-finale, it would be a 7 or an 8. Some of Urobuchi's best work thematically. The problem is that he bailed out of the middle portions of the series, making it a real uneven mess that takes a turn away from the actual interesting part of the story to do some kinda vapid fanservicey stuff. Unfortunately you can't really skip over it because there needs to be character development to move the hero from the great opening to the great ending.
Still worth a watch, just barrel through the middle.