In your former examples, Israel was building a case - demonstrating to the world that peace with the Arabs and Palestine was not really possible.
Also, they are now in a configuration where building a wall is possible, and progress is made as we speak.
The reason why they will be pre-emptive here is that Israel is a one-nuke country, and Iran knows it.
They will hit Tel-Aviv, then invade Jerusalem. They'll not bomb Jerusalem because of the Dome of the Rock.
It only takes one nuke to wipe out Israel in the way that the Arab world sees it.
By all means build a wall, but it doesn't stop the bombers. Pull out of wherever you wish to pull out of, it won't get you better press but emboldened Arab radicals and new waves of western appeasement from the left, meant to distinguish said left from other targets. Academics in the US want to boycott Israel more now, after Israel withdrawals and 9-11, than they did before.
And the fact is, Israel won't even cut off tax payments to Hamas. They are paying to be murdered. Not exactly the greatest boost to their deterrent credibility.
Iran will bide its time after it gets its first nukes. Oh it will test to let the world know. But then it will be as statesmanlike as you please, such a wonderful contrast to the warmongering west and warmongering Israel. And the bomb production line will ramp 2 bombs a year, 5, 10, 25. In a decade, they will have 200 warheads and won't have used one. They also won't have dropped support for Hamas, which won't be at peace.
They may even wait for 2-3 others to get through to widen the deniability net. Brazil, Indonesia, who knows maybe Venezuela or Syria. And then they will gives a tenth of their arsenal to Hamas and the like, and a quarter to the likes of Al-Qaeda. And the demands will begin. They know how safe it will be. They see how much we kiss Russian and Chinese tail today, while they proliferate to nutjobs, and they draw the lesson.
Two generations on, the nuclear genie well out of the bottle and every anti-western fanatic with a grievance able to get his hands on one, the west simply won't run the world any more. And that is exactly what they want. They even think it will be highly popular. Those arrogant bastards, they will get theirs.
And you want to know the funny part? The left will want to appease them even more, even after they get that far. And will blame the whole thing on the sins of the colonial past, the greed of capitalism, etc.