The AoM demo looked (and played) a lot worse on my computer than the full game. They won't "open up the graphics" in the sense that things are locked now and will be in the full game, but demos are not optimized at all. Thus people are forced to play them at a lower level of quality than the full game. For example, the AoM demo locked up whenever more than 20 units were on the screen on the lowest graphics level on my comp. The full game played fine even at slightly higher resolutions.
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."-Albert Einstein