It would be interesting to see two equally brutal communist regimes go toe to toe with each other. If they actually did, I would expect that the world’s population would decrease by a significant number. Unfortunately, the economic fallout would also destroy most of the world’s economy as a result, especially if the russians managed to wipe china off of the map.
I honestly wouldn’t mind seeing some big countries go at it for a while that the US doesn’t have to get involved in. We’ve been involved in far too many conflicts in the last 100 years, it’s time we sit one out.