You could make the argument that WW2 would have turned out very differently if Hitler hadn't been allowed to meddle with operations on the eastern front (e.g. calling a position "fortified" and forbidding retreat, which led to horrific casualties and usually ended up with the generals disobeying orders and retreating anyway, so the result was often the worst of both outcomes). Germany was broken by Stalin and Hitler before the Allies even hit the beaches.