I don't have a lot to add to this, but I thought this recent poll result from Pew was sort of fascinating. It's part of a survey of Ukrainian attitudes toward governance, and the main takeaway is that Ukrainians from both east and west are strongly in favor of remaining united. Even in the east, only 18 percent favor allowing regions to secede.
That's a surprisingly high number, but the question on the right was even more interesting. It turns out that eastern Ukrainians don't really think very highly of any of the foreign actors currently meddling in Ukrainian politics. Unsurprisingly, 46 percent don't like the EU and 52 percent don't like the US, but an even higher number, 58 percent, don't like Russia either. Even among Russian speakers, a small plurality dislike Russia.
If these poll results are accurate, there's little appetite for secession in eastern Ukraine, and little appetite for Russian intervention. That should be food for thought for Vladimir Putin.