850 sq feet - is an extra bedroom worth the extra cost?

I recently purchased a approx. 875sq ft apartment in the Union Square area, with 14ft high ceilings. It's pretty much an open space/blank canvas and I'm putting together a new floorplan with an architect I know and trust ... but who is not local and doesn't know the Manhattan market. The new layout plans for a loft/mezzanine work area over the kitchen (I work from home) and includes one bedroom with sliding doors that open the bedroom space up into the larger lounge/dining area. I like the open feeling. My question - from a future resale perspective is planning for a second bedroom something I should be doing? It would sacrifice a chunk of the living area but is doable. What appeals to buyers more in Manhattan - open space or two bedrooms?