Age of jets and missiles

I think it could be done on the War at Sea "engine". The biggest question up front in my opinion is do you want "modern" missile-age units to be compatible in game play with the existing WWII-era rules set and units (desirable in my opinion because they mixed quite a bit in fleets during the 1940-1970 period, and to a lesser extent in the 1980s). Missiles might be an entirely new rule/weapon line on ships with relatively long range, as would SA abilities like jamming, radar detection/classification, chaff, low radar cross section, tactical data links. Modern AA missiles and close in weapons systems would result in some potent AA values with extended ranges. Nuke subs would be fast and lethal, even against BBs. Jet aircraft would be hard for conventional AA to shoot down and could attack at extended ranges. We would have to deal with helos, long range ASW weapons (ASROC and similar) and VSTOL aircraft. In the cold war era, tactical nukes and strategic weapons were players at sea.  If you went far enough into the modern age, you could even start talking satellites.  On the scary end of the scale, units like super carriers, SSGNs, AEW aircraft, the Phoenix missile, the Aegis weapon system, Nuke depth charges, rocket propelled torpedoes, mobile land-based and long range bomber launched cruise missiles all become part of the game.    

Honestly, I think it would be a fun project, but not an easy one.