As Small As Possible?

One more design earthquake later - more of a tremor, actually - and the design is now at 2000 gross square feet.  This is the total area of all 3 floors, calculated from the exterior surface of the exterior walls.  At 28' wide, the house can easily fit on a 40' wide urban lot.  As such, I feel that I've finally been able to achieve the size goal I was after.  And it seems to flow better.  And have a more natural internal flow to the roof deck.

BUT: Is it too small?  Testing furniture layouts in all rooms, it seems like everything works pretty well, but the house has gone from 3 bedrooms + a multi-purpose guest room / office + studio to 2 bedrooms + a multi-purpose guest room / office + studio.  A realtor could see it as a 4-bedroom house, but I see it as a 2 bedroom with some flexible rooms that in reality would end up fixed in function.  Is this too much of a compromise?  Also, I have advised many clients and friends over the decades that anyone who doesn't build out a full basement when they have the chance will come to regret it later.  This current house design does not have a full basement!  If it did, the house would be 564 square feet larger: a crime!  Right?  Plus, more space means more space for stuff, and therefore less impetus to purge stuff that you really don't need anymore or can live without, and that's un-American.  Right?

The logical next step is to define the house with and without the basement fill-out and find out how much the additional cost would be.  Since it could be seen as unfinished (but heated) space and would not include a bathroom, it would be "cheap space".  (I tell that to clients and friends, too.)  But even "cheap" costs something, and I have a cheapskate mentality at the moment.  Wait and see.