I think we have to put it in perspective. Who has done something very important that no one else could have?
I believe that if Tobirama and Hiruzen hadn't been hokage for some reason, whoever actually was would also love the leaf, and do similar deeds. Maybe not on the same level, but they would still be capable. Madara, in attacking the leaf, doesn't deserve a spot. Oro also does not really deserve a spot for the same reason as Madara. Jiraya did a lot of espionage and fought well, but that's not on the level of, say, Danzo in terms of aid to the leaf. We don't know anything about what the white fang did really, and the current jounins did things that are somewhat replaceable as well.
That would leave Naruto, Tsunade, Danzo, and Minato. I won't include Itachi, because he is basically an extension of Danzo.
Since Tsunade's and Minato's main contributions came in single events (Minato with the Kyuubi's attack and Tsunade with Pein's attack), even though no one else could have done what they did, what they did does not reach the level of Naruto and Danzo. And since Danzo has been doing what he did for so much longer than Naruto, I believe that he, overall, has done the most for the Leaf village out of all of the villagers that we have seen (besides the First obviously).