I was considering the flaws of using Edo Tensei to "solve all the problems in the world and create a utopia", like Y had originally suggested.
I don't want to get into the specifics of defining a Utopia either, but I don't think making everyone immortal would go very far towards resolving conflict if there is still a way to mind control and erase their personalities. You have just introduced a mechanism for 'killing an immortal'. Now what is to stop different factions from fighting each other if there is a way to permanently erase them.
At the very least, I imagine World Peace to be a characteristic of a Utopia. Setting up a stratified social structure with checks and balances could go a long way towards mitigating conflict and preventing chaos (and is pretty much what people end up doing normally anyways), but it offers no guarantees of World Peace.