Well said. The reality is that this is very much (in military terms) the Russian sphere of influence. If they want to put boots on the ground, they can do so very easily.

I think the positive point of view is that unlike Crimea (which had a host of geo-political and cultural significances for Russia and Putin) the rest of Ukraine is more valuable to Russia and Putin as a buffer state than as part of Russia.

As part of Russia there would be:

• ongoing protests, which might actually strengthen other anti-Putin protest groups across Russia.

• an extra financial drain - Ukraine is broken, if it's part of Russia, then it starts costing Russia money.

• A direct border with the EU. Not so positive if you're playing military chess games and not so positive regarding trade, smuggling etc.

And balancing that, there's just not that much positive right now. By taking Crimea, Putin has a PR victory, Russia regains both it's culturally significant sites and it's Florida - and they keep the naval base.

The rest of Ukraine just isn't as strategically or culturally significant. That is not to say that Russia has no desire to take it over - I'm sure there remains some historical yearning - but there isn't the hurry there was over Crimea.