After two years of civil war and with the deeply engrained differences partition is now inevitable. It could just follow the facts on the ground, be a treaty setting up 3 countries or could be a loose federation.
Kurds: northern enclaves
Shia/Alawite: Damascus, Homs, coastal villages.
Sunni: Euphrates valley. Aleppo region.
Much is made that the opposition are islamic nutters. This is an exaggeration.
There are between six and ten thousand fighters in the islamic forces. But they vary in conviction. Many are there because they had more and better kit. Many are just devout Some salafists and some jihadists.
There are about 150,000 opposition fighters who are non salafist/jihadist.