Hi EvilCat Breath, nice to meet you. This is my first forum post, don't know how to post links or pics yet, but I wanted to ask, do you really think Putin is this theoretical, as you suggest? Two of the three areas he wants are rich in natural resources, and the third is his corridor to the sea. I find it noteworthy that he waited till September (not November) to begin massing forces.
But, Western Ukraine will never accept Russian rule. And, if I were Putin, I wouldn't want to get bogged down trying to control a people that would surely terrorize me forever. That would be an expensive drain on my meager resources.
I'm sure you're right, that Putin would like a legacy as the father of the new Mother Russia. Also, my read is that he wants control of the coal and the pipelines, which gives him both an income and some leverage over Europe
It would be very difficult to stop Putin at this point, the US would have to directly engage him and we don't seem to have the stomach for it just now. Really, the ear in Ukraine is an ethnic conflict. Perhaps the best thing to do would be to allow the country to divide itself along ethic lines. This would mean Putin gets what he wants geographically, which is about 15% of the country - but it also means the remaining 85% gets what it wants, freedom from Russian rule.