I don't think you get it, rightly or wrongly Russia will not tolerate a ring of nations along its borders being pointed daggers against its throat. This is a country that has suffered two massive invasions from the West in recent history. Once, could be forgotten, but twice says the West has an avowed aim to destroy Russia. They will trust your lot not one little bit.
In the case of Novorussia until now it has been tightly linked to Russia economically. It is this factor that counts, because a huge amount of Russia's food imports, coal, iron come from Ukraine. If these resources are lost then they may as well quit the concept of Russia all together. Even in WW2 the massive Soviet effort was to recapture Ukraine, long before areas like Belorussia and the Baltic states. To preserve the major part of their independence all these states had to do was not become party with Nato and the EU and not persecute ethic Russians. These states are incapable of doing this, hence they will be made to disappear.