Like I always say it... Danzo tried. He wanted to become the self-sacrificing shinobi that he viewed as his ideal, but he never could - once unable to overcome his fear of death, he became fairly obsessed with his idea and lost his morality. In fact, the ninjas who worked under him were closer to those ideals because they actually were fully prepared to die for him and the village, but Danzo kept hiding behind them.
He was a somewhat paradoxical person as he spoke about self-sacrifice while sacrificing others. He spoke about protecting the village while doing things that ended up damaging it instead. Ultimately, he was selfish with his desires to have the village for himself, even if he also believed that he'd be able to rule it "properly". And yes, I think that he is an interesting character, albeit a terrible person. I also think his evil deeds still outweigh his good intentions - which is more of the content creators' fault, as we hardly see what "better" things he had done, whatever it was that Hiruzen kept him around for.
