Neither Stalinism nor any other type of communism saved Eastern Europe. Eastern Europe was doing fine without it.

Eastern Europe was a backward agrarian society under incompetent rulers who were more interested in personal gain than the nation. I don't believe anybody could say that Tsarist Russia was better than the Soviet Union.

Saving would be, preventing liberal influence without destroying us or our culture by other means.

He did, actually. He kept the east out of the UN, because he saw it for what it was, a Liberal Hegemony. That's partially why he set up Comecon and Cominform, as well as the Warsaw Pact. He understand that a bulwark needed to create a balance of power in Europe.

Even East Germany, despite the reparations, were allowed to remain nationalist, and weren't constantly being told how evil they were (at least, in comparison to the West). They even were allowed to deny any complicity in the holohoax, so they weren't brow-beaten with that bullshit.

spreading feminism

Traditional family values were promoted in the east though. Letting women have industrial jobs isn't feminism. And they let some women fight in a huge conflict, they had the numerical advantage, what better way to keep it, than starting up like 2 airwings and giving some Rifles in Stalingrad. Plus, a good deal of the men were dead. Somebody had to do the work in post-war Europe. That solution was certainly preferable to what the UK did (The WindRush Plan).

bringing in third world migrants

When? And even if he brought in some, those countries remained majority Slavic/German/Magyar respectively.

he still destroyed a bunch of cathedrals and other elements of Slavic heritage

That's undeniable, however, he preserved many other parts of Slavic heritage, such as music, art, etc. His writings and speeches (and those of his government) are filled to the brim with mentions of "The great Russian people", "Our Great Land", etc. It's clear that he understood the Slavic people are one with a unique identity and destiny. In his position I would have promoted a form of Liberation Theology.

I'm not saying I agree with Stalin 100%, but I believe, by and large, the good outweighed the bad. His legacy, or rather the power of it, is much better. I am a NatCom (or NazBol, or whatever floats your boat, I prefer NatCom, and no I'm not a Marxist), so I do have a bias.