Would it really be such a bad thing for the Soviet Union to come back?
Yes. The Soviet Union was a nightmare state.
The offered a balance of power. With the exception of a couple proxy wars (not that they weren't bad) we kept each other in check, but never checkmate. Compared to now, the world did its own thing.
Tell that to Poland, Hungary, the Czech and Slovak republics, Latvia, Lithuania and Estonia. Not to mention North Korea and Vietnam. I'm sure they enjoyed doing their "own thing".
After the fall of the Soviet Union, we immediately elevated ourselves to the status of, "United States of America: Full-Time World Cop." That has not gone well. I sometimes miss the sanity of mutually assured destruction.
What? Seriously, what? How old are you? Do you actually remember the Cold War?
The fact that America is a flawed nation is no excuse for false equivalencies with brutal totalitarian regimes like the Soviet Union under Stalin or China under Mao. Those countries, under those leaders, deliberately killed tens of millions of their own people. We never want to see anything like that again.