The balconies are different sizes because I try to envision this place as not having a level ceiling. Usually I do not let a straight square or rectangular map suffice and this was an attempt to give it a sense of dimension in some other way. When the two balconies were even I considered the map less interesting.
I see more what you are saying with the chair because I thought the same thing too. In the end, I thought I should not be afraid to have items like chairs obstruct things they typically wouldn't once in a while. What I actually might do is use some smaller chairs.
Edit: Thinking over what I said about the balconies, I guess saying it is an uneven ceiling makes little sense.
I still think the perspective of the balconies isn't physically impossible and the arrangement of the room is more interesting this way.