Putin is fully aware that maintaining an empire is expensive and can get your military into countless conflicts... he learned this by watching the US. Again, if putting the band back together as you say was his primary goal, he missed out on getting a huge fish when Kazakhstan was on it's knees and vulnerable 2 months ago.
As far as us getting ourselves after Putin played the nuke card, I consider that to be a natural human reaction... and the proper reaction. The people on our side need to be made fully aware of the consequences of their actions. These lunatics think they can push around a nuclear peer the same way we push around these 3rd World countries.