If Putin doesn't care about the opinion of his own voters, the whining of the Western world wont matter (China, Iran, Venzuela and others are not against Russia).
It's one thing for Putin to get it done in a week or so. Even then, how does he plan to hold his puppet government in Kiev?
Also keep in mind that China is working towards this same "resolution" with Taiwan. It's in their interest for Russia to succeed here.