Israel is winning this war. If it weren't the Arab League wouldn't be pressing for the UN to require Israel to hand southern Lebanon back to the rocket launchers. Syria - which has ben spoiling for a fight with Israel for days now - wouldn't be stalking out Arab League meetings. The Israeli cabinet wouldn't be confident enough to formalize occupation up to the Litani. (Their failure to attack Bekaa decisively is another matter.)
Even if one accepts that Israel has largely implemented Resolution 1559, and even if one accepts that the Lebanese army is capable of patrolling the southern half of its country, post-war actions that don't thoroughly humiliate Hezbollah will only leave it around to rebuild.
It is critical that any Israeli withdrawal occur after the Lebanese government has evicted Hezbollah from its premises in the cabinet, just as Israel has evicted it from its base of operations.