I would have to imagine if the Russians somehow pull this off the insurgency is going to be much more bloody than Afghanistan. The Ukrainian people have shown they want no part of Russia, and have the backing of pretty much all the Western world. Motivated goat farmers living in mud huts ousted two of the worlds superpowers with basic weapons, IEDs, a limited supply of stingers, and the will/patience to continue to resist. Ukraine people have higher levels of education, advanced weapons, and vast support from the west.
A puppet government would fall and I don’t see the police/military protecting a puppet government. My opinion, biased by our western media and the twitter videos coming out of Ukraine, the only way to get the people to comply and stop an insurgency would be mass imprisonment and most likely a genocide.
If Putin withdraws he’s done, if he continues it will only get more bloody, and everyone is walking a fine line trying to avoid WWIII, it’s a loose/loose/loose situation.