Putin doesn't want to bring back the Soviet Union because Communism failed so hard he doesn't want to go back there. He would really want to bring back the early 1900's Russian Empire though, because he needs a "safety area" between Russia itself and all the "enemies" in the West. I *don't* really want to pull off a Godwin but the parallels with Germany taking over neighbour countries to "protect their citizens" is so eerily similar. Luckily for us, Russia is much weaker and dependedn on the west than Germany was by then.
Peace depends on whether he can be stopped politically before he goes that far ahead. Right now, gas sales to Europe make up for a ridiculously huge percentage of their GDP so they stand to lose a lot and become something like Iran if borders are closed. Sadly, Putin has the James Bond-ish mentality of the Cold War, being a former KGB spy and all, so it's not likely he'll want to negotiate until he has no other chance, and even so he has been playing the "we are the poor country everybody hates us if we have any problems is because of them" card so it will take a long while.
Not anytime soon. NATO (well, mostly US) is too large to allow that, and any attempt at imperialism could cost them dearly. Russia is not North Korea to go crazily plunging into a war like that.
But he didn't "outsmart" anybody, he just went ahead before anybody realized what was happening- and even before he could asess the consequences. He's not playing a political game, he's just chanring on, bully style. But, by doing so, he has utterly alienated the US and the EU, which funnel billions into their GDP every year. The Russian economy would implode in a matter of months if the EU stops buying gas from them and the US bans their banks and oil companies from doing business with them. Putin's plans depend on everybody else being too scared to fully stand up- which is a risk.
But while Putin just "went ahead, bully style" the west was unable to do anything about it. While "unidentifiable" Russian troops that Putin didn't acknowledge marched into Crimea, the west could not take serious action because of this lack of identity. We knew that they were Russian troops, but officially we didn't know, so we couldn't do anything about it. We have imposed some sanctions, but these are not enough at all. Just as you're saying, a ton of trade sanctions would probably cause Iran-like situations and destroy their economy. The EU, however is so reliant on Russian gas, that it would also have massive consequences for the economic growth that europe wants so badly. This is not a simple situation, and there is no simple solution.
The West are able to do something, they just chose not to. We are not so hopeless and if the situation calls for it serious economic sanctions can be dealt to Russia, as has already been admitted in this thread. That's why Russia didn't just march into Ukraine, Soviet style, because we're not in the 20th century any more and Putin knows that. Putin has always been a vocal supporter of the Soviet Union, he is ex-KGB and has been outspoken about "the glory days" since he first came to power. It's nothing new. Russia invaded Georgia outright in 2008, and has a continued presence there which seems to have been swept under the rug and ignored. The whole thing with Ukraine is just the same old Putin causing trouble again, not a returning Soviet Union...
I think it's his greatest wish, but will never be again.
The moment you attack Ukraine, a war in which there will be no victor, only unleash destruction.
As a communist, I wish the Soviet Union would return with even more power to the proletariat. In fact, if the "Cold War" was still happening and Communism was still controlling Russia, I'd be rooting for THEM all the way!
If Russia wants to take parts of Ukraine, good for them, they have my support.