One thing someone on other forums mentioned I thought was clever is that the full game is 15 gigs while the demo is only 2 gigs. I'd assume part of that (not sure how much I don't do code) is a variety of improvements, graphics, textures, and other things. Along with the usual factions, units and campaign map.

So i'm optomisitic that the full 15 gig will work much better then the 2 gig demo :) or at least marginally better