:-It has been repeatedly demonstrated that Israel is not able to protect itself from Palestinian violence through military means.
:-It has been repeatedly demonstrated that the Palestinians are not capable of forcing Israel to do anything it doesn't choose to do through violence.
:-The Palestinian violence is not going to stop while the Palestinian grievances remain unaddressed.
:-What has changed since 67 is that the Palestinian expectations have fallen - at the time, they thought they had a chance of destroying Israel altogether; now most (altohugh not all of them) have realised that the best they can possibly hope for is Israel withdrawing to the green line.
:-There is no course of action Israel can take that will not result in intermittent terrorist attacks on it continuing for a generation, I think. However, some courses of action will result in the attempts being far less frequent and less well-supported than others.
:-The Palestinians now have no leadership. Israel has finally got what it's always wanted - they no longer have a partner for negotiations. They did, until Arafat died; but even then they didn't negotiate with them.
:-As such, there is no way of holding "the Palestinians" accountable. You can - and Israel will - inflict massive suffering on innocent Palestinian civilians, and murder or arrest individual leaders deemed responsible for violence, but there is no body "the Palestinians" to hold responsible.
:-As such, the only possible route to anything resembling peace would be if Israel takes unilateral actions in that direction, and then responds to sporadic but decreasingly-frequent terrorist attacks with extreme restraint for a generation. Israel would have to act unilaterally, although preferably in consultation with as many influential Palestinians as possible, to address the Palestinian grievances, and then wait and see what happened.
:-What would happen, I think, would be that some Palestinians would accept the new status quo, and not want to risk further conflict, while others would continue to resort to violence. The relative sizes of these two groups would depend on how far Israel was willing to go.
:-I think, although I don't know for certain (no-one does) that if it went far enough (withdraw to the green line, joint sovereignty over Jerusalem, some compromise on the right of return) then the former group would sufficiently outnumber the latter to effectively stifle it, both in terms of official suppression and deprival of popular support. This would be especially possible if Israel and/or the international community helped establish a functioning Palestinian state. That wouldn't totally stop attacks on Israel, but it would massively reduce them.
:-I don't think that's going to happen. What I think it going to happen is that Israel is going to continue to kill large numbers of Palestinian civilians, destroy the lives of most of the remainder, and occupy their land, and the Palestinians are going to continue to kill significantly smaller, but still large, numbers of Israeli civilians, for the forseeable future.