The US in fact did have a serious problem with nuclear warplan targeting during the Cold War - there was essentially never a reason you could give to take a target off the list, so the plan for a good deal of time was essentially something like "hit every single conceivable target several times" (to account for failed bombs or losses en route).
It was actually one of Dick Cheney's initiatives to create a process which would remove targets from the nuclear warplan's to get the number of weapons used down to a manageable number - and end the feedback of "oh no we've assigned all the weapons - we need more weapons in case there's more targets".
EDIT: A critical element with nuclear warplan's is that you don't have one bomb per target - you generally have several bombs per target via different delivery systems with different priorities, because the key element of MAD is survivability - there has to always be a guarantee in your adversary's mind that they cannot destroy enough capability to create a winning scenario for them.
There is even a case to be made that too much nuclear disarmament could create a less stable situation, because arsenals might deplete enough that an exchange might seem survivable.
It was actually one of Dick Cheney's initiatives to create a process which would remove targets from the nuclear warplan's to get the number of weapons used down to a manageable number - and end the feedback of "oh no we've assigned all the weapons - we need more weapons in case there's more targets".
EDIT: A critical element with nuclear warplan's is that you don't have one bomb per target - you generally have several bombs per target via different delivery systems with different priorities, because the key element of MAD is survivability - there has to always be a guarantee in your adversary's mind that they cannot destroy enough capability to create a winning scenario for them.