It would still just be a regional war, with Putin resembling Ahmadinejad or Kim Jong-Un much more than Krushchev; nuclear bombs alone do not a great power make.

You're the first to say in every argument - rightly - that Russia isn't the Soviet Union. It's much weaker on its own, and perhaps more importantly has merely a fraction of its global support. Its economy would crumble within months in the case of a war; it's really just Brazil with nukes and a megalomaniac dictator. Or, to use your favourite bogeyman, kind of like what you'd get if somehow Erdogan built an empire joining Turkey with Iraq and a nuclear Iran.

Anyway, besides that I do see your point - much like Brazil, it does need to be taken seriously and not needlessly antagonized in its aspirations of having at least a small zone of influence. And whether we like it or not, the nukes do make that rather more important than it is for Brazil.

I'm thinking it would be a pretty good move for the EU to add Russian to its list of official languages right about now, and to take various other steps to reduce the tension and undermine Russian propaganda. I'm not sure if Eastern Ukraine is salvageable anymore, but at least the Russian speakers in the Baltics are.