There is an alternative to Assad that isn't ISIS.
Assad and ISIS alike are obviously bloodthirsty murderers who deserve anything that comes their way. Major HP. "Lesser evilism" in this instance is utterly disgusting, especially when there are clear and democratic alternatives in the region (like the Kurds) doing battle against both Islamism and autocracy.
The Kurds aren't going to rule all of Syria, so that is a nonstarter.
No, but they might destabilize enough of it to set off a region-wide second wave of revolutions. That's the best scenario here. Another wave of revolutionary activity to end ISIS and overthrow the Gulf monarchies.
The sort of revolution you get from destabilizing the Middle East is not something to be desired.