Necessity should be the driving force. However, from a resale value the elimination of a second bathroom could be very detramental. Froma creative stand point a third temporary sleeping area can be created by incorporating a sofa sleeper in your interior decorating.
From a practical stand point a second bathroom would be impossible to create without going backward in time and using a chamber pot.
I live in a 2/2 condo and if it were a 3/1, I wouldn't be living here. Well at least not with my wife! We can't share a single bathroom!
I also agree with Jolie, the condo board will probably not allow that type of change anyway.
I think it would only make sense if the bathroom was in really, really terrible shape.
Plus I think it doubtful that sort of modification would be approved by a condo. What about a putting a loft bed in one of the bedrooms, then you could have an office space underneath..