Putin has worked himself into an interesting position. On the one hand, he has used the pressure from his army to get the world to focus on the subjects that matter to him: the deep sorrow he feels about the way Russia gets so little respect these days, the unfair way in which Russia's former vassals were enticed to join other alliances, etc. He's got all the world leaders lining up to visit, listen to his views and offer sweeteners.
On the other hand, he is now a bit like the cat up the telegraph pole. Either he unleashes his military in the next few days, or he will have to call them back. Diplomats are trying to give him a plausible reason to do so without looking like a wimp in the eyes of his domestic audience (and President Xi, looking on with considerable interest). If he unleashes them, it has to bring a quick win: at a minimum territorial gains and consolidation of the pro-Russian militias in the Donbass; or, better, acceptance by Ukraine of Minsk 2; at best regime change in Kiev. But if he achieves either of those, what next, and at what economic cost in terms of sanctions, economic cost of occupation, etc.?
He's got to be thinking about his legacy: if he can neutralize Ukraine without a war, that might have to do for the time being. His best bet could be to pull back now and get one of his cronies to enter him for a Nobel Peace Prize. After all, they gave it to Begin and Obama: why not give it to a world leader who decided to pull back from the brink?