If you decide you would like nukes just to make the big game 'have it all', you could accomplish it by making the unit available once every technology has been reasearched. Maybe just give a single one of them... make it a kamikaze bomber unit that strikes 10 times. That way its not gonna unbalance an early game.. will exist to add color, and might help to end late game stalemates.
'thats the way it is' makes it neither desireable nor inevitable
I think the point about nukes being able to solve stalemates is a good point. And as you say, nukes could be made simple. I might add nukes to the next release, and try to add an "event list" in the notes describing what tech is opening up when/which round.