Not sure I agree with that.
The crisis came to a head when a moderately pro-Putin government was overthrown.
Long term, it's not clear to me what sort of government will replace the old one.
I think Putin's hand was, to some extent, forced by the political uncertainty in Ukraine.
But, Putin has certainly been opportunistic, too, since Crimea is majority Russian, and Obama is a comically weak president.
Well, supposedly there are Russian statements out there criticizing Yanukovych: They could have regurgitated those after Yanukovych was voted out by Parliament, expressed support for the Ukrainian people and hope to work well with a couple of the moderate pols. They could have not made any threatening moves, and maybe “house arrest” / detain Yanukovych in a nice hotel while “investigating crimes against our Ukrainian brothers” for a while. That would have defused any of the more extreme of the Right Sector types, who have never been a significant political force in Ukraine anyway. The rest, as I said, are sensible enough to have not threatened that lease. “money talks”.
Even if all that failed, Ukraine could not push Russia out of Crimea without a major provocation by Russia to energize the people.
However, Russian paranoia, opportunism, and a greater plan, I suspect, won over a more restrained approach.