Well I have to say the demo was ok, not that I expected much, it seems like alot of people thought this demo would come with half the grand campaign, a dozen historical battles, and multiplayer, demo's just don't work that way.
Think of it this way, imagine you had never played MTW, and you got a demo, you had only 1 battle, a huge army of peasants vs a big group of spearmen and some royal knights, if thats all there was, you would get pretty bored.
The demo is not ment to be a standalone game, just a minor taste of the games full glory. I do think the battles look far better than anything from the total war series before, however you have to use the right view, alot closer to the ground to see the real coolness of it all, looking from a birds-eye view like the old total war games is just not the way to get the full graphic enjoyment. I frequently paused the demo, then worked positioning the camera at different angles to view an elephant or horse charge, or a volley of skirmisher spears, and from the low down angles its a thing of absolute bueaty, of course your gonna need a hefty system, or the battles will NOT look that great. And we all know the real bread of the total war series is the strategic map, I have friends who don't even play the tactical battles, just the strategic map on MTW.
There is another weird thing I noticed about the demo, I got almost the same graphic lag (mainly at the start before the troops got wittled down) on nice high setting with gleaming helmets and shiny watter, and high-res textures, as I did with things cranked way down to the bottom, the improvment was not really much regardless. I still had to play the first minute or two with pause orders and then going in close to watch the battles.