I'm on the pessimistic side of this. The sanctions are really designed to make conditions bad enough in a country that there isn't military spending available to spend on wars... and hopefully local populace will rise up with discontent. I don't see that working for Russia... especially when oil and gas are not being touched at all and Russia is still allowed in international banking. Then you combine that with 600b in reserves, Russia can withstand a war with Ukraine for years. As long as Western Europe keeps the taps open on Russian gas, Russia has the funds to continue war. Being a practical dictatorship, the uprising won't happen easily. This isn't a little Arab Spring sort of thing that has to happen. This is a country that took 15-20+ years to really have it happen and even then it was the gov't that threw in the towel. Putin will never do that.
So with that said, I don't see a situation where Putin doesn't at least end up with Eastern Ukraine (I think that is his real angle... for now). There will be lots of fighting and that will be the 'compromise' given out. Ukraine won't have much of an option but to accept to even stay alive as a country. The West isn't invested enough to go to war with Russia over Eastern Ukraine. From the Putin will mend his wounds and start planning the movement to take over Moldova from there and then back for Western Ukraine. I'm certainly not an expert on East vs West relations, but Putin's playbook is pretty obvious with his other moves. Posture, use force, threaten more, offer a compromise that gets him half of what he really wants, let the West claim victory, circle back around when the finances and military have been built back up.