I guarantee you Soviet Janeway would not have killed Tuvix
Or do countless warcrimes
Mirror Universe Janeway leading the Romulan People's Republic in its liberation of the Alpha Quadrant, and most certainly not genociding the Tuvix population.
I like the tidbit of this au that instead of just being vulcans again they decide everyone must be a romulan because the name is way cooler.
More medals = more communism