The nuclear winter would be an interesting feature. Yet, I'm not sure about the "experience, economies of scale, etc." involving the manufacturing of nukes. If you want it to be a true "game-ending" condition, then simply make that nuke more destructive (and expensive).
@Pisarz I'd say, the first comparision was actually way more accurate, as we don't really know how big those machines are. I mean, I'd say a Scout is the size of a car, but I'm not really sure because it was never mentioned how big they were.
@Encrypted Well Archiv that are kill tons of Enemys can be but that must be a few must of the can be Less enemy but in some time or a number of Games
Something like Dunno 100 kills i a Game With Gorilla Punch
1000 HP Heal With Medic i 5 minutes