It was more to impose communism rather than
I would rather say reinforce, they aided Cuba becaouse they were commies, they aided Vietnam cause of commies, N.Korea cause of commies and so on. If anyone wanted to impose it was their "puppets". They had puppets to reinforce their defence not to spread communism like they wanted in 1917.
Defensive they were but they also kept an iron grip on Poland and still looked outwards.
Yeah but not from point of world domination, but more of security. You can compare the goals of the soviet union from 1917 with after Stalins death in 1953. They didn't invade anyone anymore like they did with baltic states, Poland or Finland. They supported only places were there ere commies in trouble and were an good opportunity for a better defence.
The pickings were pretty easy given the powers involved.
That yes, still blood had to be spilled