I would wish that the game was designed so you actually did care a bit more about your decisions and their consequenses, moral etc. But you just see a city hex with a number on it that gets halved from 20 to 10 after you have nuked it, and a bit of fallout and pillaged terrain that you can clean up fast with your workers. After a few years there will be no signs of a nuclear holocaust at all. No long term effects, no suffering just halved numbers on city tiles and you just clean it up and life goes on. No atomic winters, no disastrous increases in death from cancer, no lands that are radioactive wastelands for a thousand years. The people in the land that had one of its cities nuked will actually be happier because happiness stands in relation to the number of your population. If it decreases people get happier. Facepalm. What a wonderful world with easy sollutions to the most horrible weapons ever made! And all the civs are mad at you because you waged a war, no matter if you used nukes or not. The civ games have always been a bit sterile when it comes to these matters.
If you feel any sadness or remorse when you destroy cities its because of your own imagination and roleplaying, not the game itself unfortunately. Civs that act as irrational as they do in CiV are not waking up any emotions in you, except emotions of frustration and hatred over how false and backstabbing they all are. Building a relation with a civ is non existent. The most friendly civs will join the wave of denounciation or dow against you any turn, no matter how much you have done for that particular civ. A small civ will even hate you for defeating civs that attacks that small civ. You dont feel a thing when you wipe a civ from the map, because you know that all the civs will sooner or later try and do the same to you. Thats the basic game mechanics.
This is a good thread though, because it points out one of the major issues with the basic concepts of the Civ-games.