I love the idea of a Cold War variant. I think longer term the site would probably have two variants: a global game and a straight NATO/Warsaw Pact variant.
The global game would be presumably played on a map like WWIV and you'd have not only USSR/USA but also their allies. To keep the game realistic you'd also have a number of neutrals (the most significant of course being China who was pretty much on the fence after the Sino-Soviet split in '61 and detante between China and USA after Nixon's visit in '72).
Personally while the nukes would be good, let's be realistic. If one side is losing and resorts to nukes, the otherside would retaliate back. So yes, there would be no winners only losers. That'd mean it would be all too easy for game after game to be lose-lose. As a result over time players would probably give up playing it knowing chances are everyone would lose (and your Diplomacy ranking would be constantly downgraded.) I'd suggest instead we keep it to conventional warfare.
I'll focus my comments though mostly to the Warsaw Pact-NATO variant which I think has the potential for more complexity in gameplay in some ways.
To have better "balance" I'd suggest both the European NATO and Warsaw Pact countries (minus USSR - I'll get to that) have roughly the same number of SCs. That said, you could have more Warsaw Pact starting units than SCs, as they're better positioned to advance on neutral/non-aligned SCs (Finland, Austria, Yugoslavia - Tito and Stalin fell out in '48)
Re: USSR I'd suggest you either leave it out entirely (as this would create an unbalance with US SC's not present), or create USSR and USA as "off map" SCs (just like Spain in Dutch Revolution). You could probably have a number of USSR SC's physically on the map that could be captured, but maybe certain SCs are "off map" eg Leningrad, Moscow, New York, Washington DC etc). This would mean no side could totally "lose" all their SCs, but presumably you'd set victory conditions where you needed a set number of SCs to "win".
Re: units, if you don't have nukes I'd suggest maybe an armored unit and a new paratrooper unit. This could effectively be like the Knights unit in Germany 1648. It would allow the players to drop units beyond the iron curtain (either way). I'd also suggest that NATO has one or two paratroop units on the iron curtain border which would "support" a NATO unit in West Berlin (which gets around the issues we've been discussing re: West Berlin.
Personally I'd suggest Switzerland stays totally neutral and can't be invaded (like Classic).
If possible with the coding I'd also suggest that NATO (being the "good guys"/supporters of democracy) can't invade a non-aligned/neutral SC. I'm open to them being able to support standing neutrals though, and being able to take a non-aligned/neutral SC post a Soviet invasion.
I'd also leave out any SCs on the NATO/Warsaw Pact map from North Africa as that would distort play.
Ok, that'd my two cents on the idea. Feel free to give it (or bits of it) thumbs up or thumbs down. Hope it helps with people's ideas.