Comment 7 for bug 1152674

the magic is the problem in your suggestion fuchur: it would behave differently depending on some settings. If you want to dismantle quickly you might be surprised by the additional waiting time (during which a building might still be attackable for example).

Another way would be to show an additional window before actually dismantling where you can check which wares you want to salvage - this would be another UI element though that would never be used anywhere else. Still, it is explicit, easy to understand and would meet all user requests in this discussion. It would mean at least one additional click for dismantling, but we could merge this with the "do you really want to dismantle this site" dialogue with CTRL + click keeping its current behavior.