My understanding was that Israel doesn't want to topple the Assad regime. Radical Islamists and Hezbollah will fill the void when he comes down ... and he will fall eventually. I am lead to believe that Assad is the lesser of two evils.
I've heard that analysis and kinda of agree. Problem is that Assad needs to understand Hizbullah will not be tolerated any longer, Syria still has much influence with Hizbullah even though they have moved out for the most part. I'm not saying take the Assad regime down but the message needs to be sent. A few sorties over Damascus, military installations in the Bekka Valley and perhaps a brief armored thrust a few miles into Syria proper (or at least deploy in strength in the Golan). Make it hurt a little. Now as far as Iran goes, we need to be giving Israel overflight rights thru Iraq . . .