Shortly after the First World War a Swissman (whose name I forgot) was most impressed by what he had heard about the trench war. He concluded that machineguns were the weapon of the future. He campaigned for an all-machinegunner Swiss militia, which would supposedly be invincible then.
This is a rather normal human behaviour: Recent, impressive experiences have often a disproportionate influence on one's thinking. It's similar to how some people seriously believe that it's an utter necessity to "Bomb Iran, now!" - shortly after a barrage of alarmist reports and commentary. Again and again, for 20 years - and in days such as today, they barely remember Iran's existence.
The events in the Ukraine impressed a lot of people as well. Putin somehow invented a new way of war or such (never mind that he basically did what a British political satire TV show explained in detail three decades ago). Then they go on to assert that Putin would employ the very same approach in another conflict as well.
And that's stupid.
His approach isn't to employ troops without badges in an invasion -> *black box magic* -> win!
He's rather successfully doing what many aggressive governments have done in history and will keep doing; he exploited his freedom of action, stayed below the violent response threshold of the other great powers. His actions in the Ukraine were tailored to this country's domestic conditions.
Conflicts in which he wants to achieve more than possible without exceeding said threshold are likely to take the shape of a strategic coup de main with conventional forces. Conflicts with a low threshold and little ambition on Putin's side may see much less brazen moves than on the Crimea or in the Eastern Ukraine.
Now excuse me, I go visit some places in the intertubes where people embarrass themselves in a funny way by pretending that Putin would repeat the exact same scheme from the Ukraine elsewhere.
related: 2012-07 Niche exaggerations