No, Helvetica, you are not right. Even if there are a lot of factions, there is globally a coherent action against the regime and today against Isis. Al Nosra, Islamic Front, and FSA (which still exists principally under the name of a new coalition the Syrian Revolutionaries Front  they controll large parts of Idlib Governorate, of Aleppo countryside, Aleppo itself, Homs northern "liberated" countryside, and in the South and dont't forget other factions which are close to the "FSA" like the newly formed Army of Mujahiddine or like the coalition of the Soldiers of Sham in Damascus) are today united in a coherent action against Isis, which shows that Isis has become a new player in the war distinct from the regime, the YPG and the rebellion.