I friggin' hate when people call Danzo evil. Everything he did was for (In his own eyes) the well being of Konoha. The reason he had tricked Hanzo into killing Akatsuki was because Akatsuki was preventing Root from stopping Konoha's peace treaty with Iwagakure. While this seems horrible, just remember that tons of people died in the Third War, and Danzo was probably hoping for the complete annihilation of Iwagakure, instead of 'just another peace treaty'. Considering that the last two wars ended with peace treaties, Danzo was probably well within his rights in trying to stop it.
And as for helping Orochimaru with the senju cells and such? Who's to say Danzo didn't know about the Sage of Six Paths as well? Maybe he had his own plans for obtaining the Rinnegan. And as for the matter of Shisui's eye, who WOULDN'T want Kotoamatsukami?
The second it seems another Great War is going to break out, just Kotoamatsukami the opposing Kages.