If you want a playable WW2 Grand Strategy game, try Gary Grigsby's World at War: A World Divided. This is the 2nd game, not the original. To me, it has almost the perfect blend of detail and playability. The AI isnt bad (certainly will teach you things for a while), but once you're experienced you have to start giving it handicaps.
The 'final' patch for it just came out a few weeks ago and I believe it hammers out the last of the real issues with the game over the years. Support for the game was quite good and I believe it's in a very good place now.
If you try it, lemme know what you think!
As far as World Supremacy goes, I'm still in 'watch and see' mode too. I check the forum to see if anything happens, but I'm not holding my breath. If something does, great! If not, well it wont be the first time I've wasted money on a poor PC game and I'm sure it wont be the last. I realize that is a lousy attitude in some ways, but I think it's just being realistic and in fact, I have many board games in the same category...we play them once or twice and then not really much again.