Hitting anything in Syria would constitute a major escalation, and may not be advisable at this juncture.
Either we're in a war against terrorists and those who support them or we're not. We can't continue to fight half way and with gloves on. The world knows of Syrian mischief without any doubt. Now is the time to confront Syria directly. A few well placed powerful bombs should do the trick. It would be Syrian choice after that. Ten to One they'd back off after screaming their heads off.
I'll take that bet. They have no intent to surrender to Israel and lose face. They possess WMDs and they will use them, either on Israel or, if capable, on the United States. Hezbolla takes their orders not from Syria, but from Iran and their nutty leader truly believes his mission on earth is to trigger the "end of days" scenario signaling the return of the 12th iman. He believes war with the United States is not only inevitable but highly desirable. He doesn't believe Iran can win such a war, but he does believe islam can.
This may be just a trifle simplistic. Right now, the matter is Israel's call, and I think they are familiar with the threat assessment.
And right now, many possible combatants are sitting it out. I consider it inadvisable to make their bad choice easy for them.
As long as Syria is only a supply point, and not directly engaged, it is best to leave it that way. If Israel can obliterate Hezbollah without pushing Syria into action, that would be the best solution. They would have the entire country of Lebanon as a buffer zone, and the Lebanese could get back to a relative peace and prosperity.