yes, well, I'm beginning to think warheads in general would need to be left out of any pvp game - nukes, lightning, etc all are too powerful without some sort of repurcussion.
I have, on the other hand, considered a new level of 'progress' - citizen malcontentedness. As this gets higher, your resource income gets lower..
Dropping nukes might be nice for the initial shock and awe campaign, but after that you better be able to stand your ground without much resources