People have often called nukes UP (ridiculous given the time that passes between turns) in civ games, yet in every civ game I've seen them, they are devastatingly cost-effective when used with any semblance of strategy. Tell me, how many other in-game weapons can completely wipe multiple units of the same or greater tech instantly, ignoring terrain and sometimes at less hammer cost than what they destroy?
Not many.
I always found it interesting in civ IV that people would claim nukes were too weak there, and yet with a little investment into them a 10 city high level AI could be wiped of the map before it even got a turn after declaration. Some weak unit! Given its equalizing potential in civ V, I suspect it's more of the same.