This started as a clarification to some of what I wrote in the previous post...
I was against the disengagement for a variety of reasons. However, I did see the possible good that could come out of it - namely, the reasons DovBear mentioned, plus the ability to attack strategically in Gaza without having to be concerned with hitting Israelis who live there (among other reasons). I agree to an extent with what Harry Maryles said today - I don't see the "I told you so!" about disengagement in terms of what Israel is doing.
I do, however, see that those who cried out against disengagement were right in other ways: As much as the international response has been a little less anti-Israel than it was in the past, the main statements we're hearing from all over are "restraint, restraint, restraint." This, even when soldiers have been kidnapped, which is generally viewed with more sympathy by the world. The claim that Israel would be able to take advantage of the fact that they had completely withdrawn from Gaza (and the Golan) simply isn't true.
Furthermore, Israel should have been responding like this all along. As soon as the first rockets from Gaza hit, Israel should have responded with full force. Most people don't seem to remember this, but in the first days after disengagement, Israel actually did respond - and had international backing. However, after a couple of weeks, Israel stopped responding... and when they decided to again, that international backing was gone.
The key here is that disengagement really could have worked: If the follow-ups we are seeing today would have been carried out at the first signs of attack every time they happened throughout the year. Had Israel done so, disengagement would have been fresh in people's minds, and the Palestinian hypocrisy impossible to deny. Instead, Israel waited (perhaps Sharon's stroke caused it, perhaps elections - Israeli or Palestinian, perhaps something else), and they lost that ability to respond and be backed by the world.
Whether or not you agreed with disengagement, it was a failure. Reasonable minds can argue as to whether or not it was a failure as a vision; but there is no doubt that it was a failure in its (lack of) execution.