I'm pinging Southack, as he has had some good comments on these types of matters, as does RightWhale.
It seems to me that any signs of weakness by the Arab/Persian parties either directly or tangentially involved in this war will be seen (and exploited) by Islamic radicals. To that end, I believe players like Assad CAN'T show weakness or risk a significant balance of power shifting within their own country/areas of control and influence.
The above is my concern - that parties such as Assad or Hezbo, etc can't back down or they will fall out of favor with those that provide them support. That can lead to posturing, tough talk and some wrong - very wrong decisions, which can have unfortunate results.