Most area's seemed of good size to me, although the very meager architecture made the ceiling look very low in especially that 200002 pic. It's not always the actual size that counts but how it feels towards the player. A guy once made a map with a ceiling that looked way heigher than it actually was, a bit of trickery can do a lot.
For example, over-stretched textures often make you feel very bad about the map's proportions. Try a grate texture 4x4 scaled and you'll feel yourself very small. Several things other than the real size of things affect the way a player 'feels' the proportions.
Detail isn't the small extra thingies and brushes but also the way things 'feel'. The way architecture is represented, the way rooms look logically placed and seem to have a purpose.
At this moment I'm working on a map featuring a small outside industrial area. Lots of buildings just don't work for me because they don't seem to have a purpose. That's a bit of detail too...
No deadline? More time to spend on the maps that means, I hope? Good...
And good luck, of course!