Well, I think the reason why this merger happened need to be determined. Right now I'd say that the vast majority of people living between the Jordan River and the Mediterranean are against such a solution, and it was the same in the 90's. So if it happened in the 90's, it means that the vast majority of both Israelis and Palestinians (and it has to be the VAST MAJORITY, because otherwise a conflict, especially this one, wouldn't end in a merger) are supportive of a one-state federation/unitary egalitarian state. And that requires huge changes in the region's history that would bring the two peoples closer, and also a different political situation because it seems to me that the politicians of that era would never agree for a one-state solution. And you can't just leave it at that, you have to say what changes happened that made this union possible, and long-lasting. Moreover, they probably require divergences on a GLOBAL scale to allow such huge shifts in public opinion, so you also can't say that the world keeps functioning as it did IOTL. IMO, this scenario isn't plausible, and can't really discussed they it's presented in this thread.