I'm still not convinced removing Hitler before his invasion of Poland would have been a good idea, it seems possible someone like Himmler would be just as capable of picking up Mein Kampf as an ideological framework to continue imperialism and kick off genocide. "Look what the Jews and communists did when we tried to stand up to them, they killed the leader of our movement," etc etc.

Once the genocide started though I do thing all considerations, including national stability and continuity, are lower priority than ending the genocide as fast as possible.