Quite so. I do think what you suggest entails at least a ballpark, or at least a part of town level of specificity for at least 2 of the quantitative specifics.
So what I'm suggesting might be satisfied by the advocates of war saying "we need a million troops and a shitload of $", Or, "we needs boots on the ground for 50 yrs". There probably are some single condition statements that would make the point. "We need a war tax to do this." "We will need to start drafting people into the military to do this."
I don't know if Obama has it right or not. But it seems that those who say he has it wrong, that it is not enough, don't quite say what is right, what is enough. I will take this sort of thing seriously when it says "the US and allies should invade Iraq/Syria with x number of troops, be committed for a minimum of x years at a cost of $x to be raised in the following manner. After that, I/S will be (select where on the continuum of tolerable to glorious), ruled by (select us or them)." Or something.
The point is not to assert one knows the course of history, but to be clear about what one's goals and intentions are.