1. The client states weren't client states. They were de-facto annexed polities with centuries of distinct characteristics. After Soviet Union fell these countries could resume their legitimate existence.
2. Russia has always been an imperialistic, genocidal and brutal country, incapable of creating anything of lasting value. A country on the Russia's border has no reason to be categorized under "russian dominion".
Legitimate states have unalienable right under international law to guide their own path, regardless who their neighbours are.
If your neighbour is Russia, you really want to ally with a larger party.
"Who was it pushed NATO right up against Russia's border."
Nobody PUSHED NATO. This is what is wrong about the posting above. The CCE countries, Estonia, Latvia, Lithuania, knew very wall what Russia was and that it had not changed.
They wanted to join NATO exactly because they knew Russia would one day again attempt to annex them.
Unless Estonia was in NATO, Russian armors might very well be now in Tallinn.