For Israel Assad is no longer the enemy as the Iranians in Syria have become separate entity over which Assad probably has no real control.
Assad has no control over the Iranians at all. Putin, on the other hand, can tell the Iranians what to do. Just a matter of who really wants to throw down. He doesn’t want to have to pressure them, and they would get utterly wrecked if shooting started.
All the same, Israel is saying that Assad regaining power helps their security.
Although Syria is an enemy of Israel it is totally defeat-able by Israel. The greatest threat for Israel by Syria is an unstable state guided by Iran. Oddly the despot Assad in firm control of Syria is good. He well knows he can not defeat Israel and sure as hell wants to defeat the internal elements in his own nation.
PS
Obama and Clinton are what made this insane war in Syria that did not need to happen.