http://www.youtube.com/watch?v=ic6dKnv3WdU - I don't see any type of leggings on the Elven Armor at 3:52 in this video. Now, it's also not showing the other Elven armor pieces in the "Elven Armor" selection, which leads me to believe that the term Elven Armor does not stand for the complete set of Elven Armor, otherwise you'd see what the player currently owns of the whole set ( boots/gauntlets/helmet) displayed as well. That being said, I still don't see any leggings or greaves attached to the armor so one could also assume that they have renamed cuirass to armor, or perhaps they have several different labels, like briastplate, chestplate, cuirass, armor, etc. for different types of torso-covering armors. The boots don't have leggings attached to them either, so where is the leg protection? Just because it isn't in the inventory list in the demo doesn't mean we should assume that greaves or leg protection of some sort are not in the game.
I don't think we should get all worked up about this until BGS gives us a definitive answer on it. There are many factors, Smithing being the main one, to take into account before we bash BGS for re-working their apparel system.
Since we're making assumptions, let's assume something positive and say maybe they are working on making it so you can wear basic clothing underneath your armor. maybe you can wear robes, cloaks, or capes over your armor, which in turn will be over your basic clothing. All this could be for Enchantment Stacking purposes.
See what I did there? I made some positive assumptions about this whole situation, but at the end of the day, we're all still just assuming things without any real facts. We don't know what armor customizations are going to be in the game because they haven't told us yet.
To the OP's point though, even if torso and leg armor does end up being combined, it's not going to stop me from buying this game on day one.
I think everyone needs to chill out for a moment...