There is no reason to think Russia would not be acting every bit as aggressively with former Warsaw Pact nations (and especially former Soviet Republics - Baltic States) as they currently are with Ukraine, et al. There is certainly a humanitarian benefit to having these nations free of Russian tyranny, even if you could persuasively argue that current Russian aggression is linked to the expansion of NATO (I am not convinced).
Maybe we didn't go far enough. Maybe we should have formally invited Russia to join NATO, and pushed Europe harder to put them in the EU.
Not sure that would have worked either. Maybe the Russian people are just too different from the west to make any relationship work.