One of the best blogs on current Ukrainian affairs (despite its home page) is Current Politics in Ukraine, run out of the University of Alberta’s Stasiuk Program for the Study of Contemporary Ukraine. (You can always get to it from the link in the right-hand sidebar of this blog’s homepage.)
One of its recent articles, by Stasiuk Center director David Marples, analyzes the five major grievances of the pro-Russia separatists and assesses them for their credibility and actuality.