Nukes are good to have a few of, but frankly their unlikely to be ever used in a state to state setting as the gains are less than the losses.

Europe has enough nukes to make MAD a reality. In total there's a couple of hundred warheads.

The principles of warfare have been radically altered over the last 100 years, unless you're using very vague principles. WW1 especially shows the fallacy of "nothing has altered". One modern destroyer could single-handedly smash entire fleets from only a few decades ago; nice big tank collections can be scrapped within hours with weaponry mounted on troops / planes / hum-vees / helicopters. Nothing can be made heavy enough any more, which was certainly far less the case not so long ago.