Regardless of the limitations that Congress puts in the "authorization to use military force" the fact is that there is a very strong possibility that the war in Syria will escalate and get very ugly. I'm unsure about the decision myself. We have an interest in punishing the use of WMD, but none of the factions in Syria are the kind of people we want to align with.
Congress authorized war in Iraq in the manner of a patron ordering a dish at a restaurant. Then, when the WMD didn't turn up and the insurgency turned out to be harder to beat and uglier to fight than we hoped, many people in the United States wanted to send the dish back. "Waiter, this war is too spicy! Take it back!" But the war didn't go away just because we came to think it was an ugly and misguided one.
There are many reasons to believe that a war with Syria will be short and relatively pain free (for those of us not under the bombs or in the ships and planes charged with delivering them). But there are no certainties in life, and especially not in war.
In voting to authorize force against Syria, Congress will be hoping for a short and inconsequential war; Syria, Russia, Iran and Hezbollah, however, will all get to vote on what kind of war we actually have.