I think he could have been handled better writing-wise, he ended up never really accomplishing anything. He is supposed to be a morally grey character, but Kishi pretty much forced us to consider him a villain, just because he doesn't have Will of Fire. Danzo was way too paranoid, which made him make strategic mistakes (controlling Mifune just because "I would have probably appointed you as a leader anyway" wasn't good enough, noo, he wanted to make sure). Also, Izanagi wasting, seriously? So in short, I think he had more potential as a character, but Kishi antagonized him too zealously. One Hiruzen flashback wasn't really enough; I'll give him a 5.