ikalugin,
you underestimate the personal missionary spirit that probabaly now drives Putin as well. There are Russian "zones of ionterest" already in Moldavia, and around Odessa (I wonder why Odessa gets so little recogntiion her ein the Wetsenr media). Also, Putin repeatedly mentioned in last speeches the idea or conception of "Nova Russia". This is a terriotiry that has precedneces in history leading back to the time of Katarina. Here is a map.
That territory bites quite a huge bit out of the Ukraine, the complete south and east, and of course access to the sea would be blcoked for the rest of Ukraine as well. It closes the löand connection from Russia to the Crimean, to Odessa - and borders to the conflict zone of Transnistria/Moldavia.
If that is what Putin aims at, the n we still have quite a big conflict before us.
The sanctions will drive a sting into Russia, no illusions about that. Whether they make Putin change his policies, is something different. He has driven himself so far ahead that I think he even could nto move back jnow anbym ore even if he wanted to do so. It wouold weaken himsaelf at home, damage his public reputation, and foster dissatisfaction with the conservative elites.
Tpo prevent the Uk,raine turning into a NAT= meber, to prevent NATO navy units stationed in Sevastopol, to finally get beyond the notorious conflicts with Kiev since the orange revolution, and to enforce a change of the Ukraine into a political entity where Russia directly or indirectly could interfere and keep the ukraine within Russia'S sphere of influence (divide et impera by federalism and an autonomous East), as well as getting the Crimean, I think were minimum objectives of the Russian reaction sinc elast autumn.
Whether it will be left to this - or will become a bidding for a Nova Russia, we will see soon enough.