The immediate winners are Israel and Turkey. Israel's security is improved, while Turkey has succeeded in projecting power in the Levant. This advances Erdogan's goal of creating a neo-Ottoman empire.
My guess is that it will take years for a stable new regime to emerge in Syria. With the country exhausted, a relatively peaceful era may be in the offing to the degree that the Syrian people have anything to say about it.
How is Israel's security improved with the likes of Al Quaida in control of Syrias armaments?