As a person, who saw the start of the conflict [from the Russian side of the border, but well-informed about the events in Ukraine], I can make some remarks:
1. Pro-Russian separatist in Eastern Ukraine are much more “pro-Russian”, than “separatists”. In fact, they fight not for independence, but for annexation of their regions to Russia. Annexation of Crimea gave the pro-Russian movements hope, that Donetsk/Lugansk/Kharkov/Odessa/Nikolayev – will soon become parts of Russia to. I March-April 2014, I heard from people from Donetsk: “Russia soon took us to his, and we will receive a salaries and pensions, as in Moscow. War? What war? Ukraine passed Crimea without the fight, Ukraine will pass Donbass to”. I think, if Russia refused to annex Crime, those dreams would be broken. Also, we must remember, than the war in Donbass start, when Igor Girkin’s squard crossed the Ukrainian border and took Slavyansk in Lugansk region of Ukraine. Girkin is [he is still alive] a hard Russian imperialist, who took part in annexation of Crimea, and wanted do the same in Donbass. Without annexation of Crimea – I did no think, that Girkin wanted to continue the game.
So, in one sentence – I think, that Independent Crimea would mean no the war in Donbass at all.