I think layout is very important, as is your clutter and lifestyle, more so then the actual square footage. What is reasonable to me is not necessarily going to be reasonable to you. We have 2 home offices for example as both my husband and I work out of the home. Thus we need more space then the average family where people work outside of the home. I do agree that houses seem to get bigger and bigger these days with a lot of wasted and/or unused space which eventually gets filled with stuff.
ITA w/this. I live in a 3000 sq. ft Victorian and at times it feels small. In part because there are very few closets (2 to be exact) and if it were not for the attached barn/garage we'd have very few places to put stuff. Also in our case, dh works from home so out of the 4 bedrooms, 1 is a office; plus 3 of the bedrooms are attached with no hallway seperating them and with a 15 yo and a almost 2 yo, I realize that we really don't have as much room as we originally thought.
So a poorly designed house with more space can be worse than living in a smaller but better designed house/apt with closets, etc. A good layout is key.