Anyway, if you’re going to have nuclear weapons in the game you really do need to drop the pretense of them being some kind of surgical tool. The A-bomb is an indiscriminate terror weapon that murders massive numbers of innocent civilians with really very little military usefulness beyond that threat. A house rule for nukes should be couched in terms of genocide, which is their only real purpose.
I agree with you that in WWII (and less so as the weapons became more sophisticated in the Cold War), nuclear bombs were more of a psychological (you used the word “terror”) weapon than a tactical one. After all, Japan didn’t surrender because their industrial facilities were irreparably crippled from the bombs at Hiroshima and Nagasaki, it was because they feared further attacks.
I do think that a house rule that implements atom bombs should account for this fear (perhaps an instant surrender mechanism?).
However I think you go too far in stating that the A-bomb is an “indiscriminate” weapon used for “genocide.” The bombs used on Japan had very specific targets, with very specific objectives. From atomicarchive.com:
Some of the important considerations [for target selection] were:
1. The range of the aircraft which would carry the bomb.
2. The desirability of visual bombing in order to insure the most effective use of the bomb.
3. Probable weather conditions in the target areas.
4. Importance of having one primary and two secondary targets for each mission, so that if weather conditions prohibited bombing the target there would be at least two alternates.
5. Selection of targets to produce the greatest military effect on the Japanese people and thereby most effectively shorten the war.
6. The morale effect upon the enemy.
These led in turn to the following:
1. Since the atomic bomb was expected to produce its greatest amount of damage by primary blast effect, and next greatest by fires, the targets should contain a large percentage of closely-built frame buildings and other construction that would be most susceptible to damage by blast and fire.
2. The maximum blast effect of the bomb was calculated to extend over an area of approximately 1 mile in radius; therefore the selected targets should contain a densely built-up area of at least this size.
3. The selected targets should have a high military strategic value.
4. The first target should be relatively untouched by previous bombing, in order that the effect of a single atomic bomb could be determined.