I'm not sure why Israel would be freaking out over the destruction of an enemy they helped to eliminate in Iraq and Syria?
Isis had its sights on Israel. If they weren't defeated in Syria they would have eventually attacked Israel.
Israel,SA,Egypt have been working together along with Nato and other nations towards eliminating and preventing the spread of Isis.
Here is an article on the spread of ISIS...[www.dailymail.co.uk].
Africa is my guess where the majority of reforming will take place. I've heard some have split off into milder splinter groups which may find more favor in more moderate Muslim countries?