Leaving Gaza was a good idea

Only it was the wrong people that left.
It should be obvious to everyone interested by now that for Israel to decrease the area of land it actually controls and occupies ("illegally" or otherwise) means that the enemy's land is INcreased. Apart from the moral victory this signifies (and that IS what it is), it also affords more and more wannabe-Jew murderers a shot at some Jews. As is happening with increasing frequency at Sderot.
In the beginning no one took these selfmade rockets serious. Now people have died, and more and more are getting injured.
As I said before, the Arabs are just lobbing these things over the fence at random. If you miss, hey, they came for free, courtesy fot the EU, UN and US. And every once in a while, you get lucky. So it's really a win-win situation.