I am not in favor of a wall of any sort. It divides the Land of Israel. Not just this, but (Heaven forbid) it could not only be used as a means to keep Arabs OUT, but it could also be turned around and used to keep Jews IN...I.E....as in kept in their place by the international community etc.
Back to the ghettos anyone?
Not just that, but heck....the Palestinians could shoot over the fence, climb over the fence, dig under the fence, blow holes in the fence....
It's a waste of time, effort and space.