There is general agreement that the rebels have lost the seven year civil war but the fighting is far from over and several major unresolved issues remain. In the [northwest] there are the remaining non-ISIL (Islamic State in Iraq and the Levant) Islamic terror groups (over 20,000 fighters) that are currently surrounded in Idlib province. ...
In the southeast there a few thousand armed ISIL members fighting to the death. ...
In the [northeast] there are the Syrian Kurds, who are seeking an autonomy deal from the Assads. That is violently opposed by Turkey, which is risking its NATO membership as it tries to force out two thousand American troops who advise and assist the Syrian Kurds and then eliminate armed Kurds in the area.
In the south there are the Iranians, seeking to build bases and establish pro-Iran forces on the Israeli border. Iran and Israel are actually at war and Iran has been losing. ...
The Assads also have lots of problem restoring law and order to Syria. The war killed over half a million people (most of them Syrian civilians) and drove a third of the population into exile. There are dozens of pro-Assad Syrian militias that have to be demobilized. Since many of these militias exist mainly to protect a specific part of Syria (where the militia members and their families come from) there will be reluctance to demobilize until it is safe. Then there is the economy, which is a mess. GDP is about half what it was in 2011 and limping along because of economic aid from Iran.
Does restoring law and order in even the areas of western Syria that Assad nominally controls (where militias, Hezbollah, or Iranians actually rule) include suppressing rebel insurgents and terrorists who no longer control territory as they did in the civil war and multi-war phases of the war?
Assad will have problems holding on to power now that his supporters aren't held together even as the death toll and destruction skyrocketed out of fear of a jihadi victory. Assad probably likes having foreign powers like Iran, Turkey, Russia, and America all vying for influence to allow him to balance between them to stay behind the big desk.