The Golan Heights is a vital strategic part of Israel’s territory and was taken at a great cost of lives. The two major threats to Israel retaining sovereignty over the Golan Heights came from international pressure to give it away to Syria in exchange for a peace treaty and from its Druze residents who have refused to accept the territorial transition.
The prospect of a peace treaty now seems absurd. If Assad remains, then the prolonged civil war will have destroyed his international credibility and his feasibility as a peace partner. Even proponents of a peace treaty with Syria have been forced to admit that had Israel made a deal with Assad, it would now be worthless, much as Camp David is now worthless. If Assad falls, then a peace treaty with his Muslim Brotherhood successors is unlikely. At most they might offer a truce in exchange for territory and even proponents of the old Assad deals would have trouble with the idea of trading the Golan Heights for a temporary truce until the Muslim Brotherhood regimes in Egypt and Syria feel sufficiently ready for war.
The Druze on the Golan Heights, as opposed to the Druze in Syria, have maintained a tribal allegiance to Assad, but that is beginning to change and there are reports that many are now obtaining Israeli citizenship which they had refused in the past. If Assad falls, then the Druze will be considered heretics or infidels in an Islamist Muslim Brotherhood Syria and that will break those old ties and turn the Golan Heights Druze into loyal citizens.
The flip side of the Sunni Islamist consolidation of the region is that minority Muslim peoples now have no choice but to turn to Israel. There will be no room for the Druze in an Islamist state, and that leaves them with a choice of Israel or nothing.