I don't have much constructive advice on how to render it better, though you could look at kerkythea which I've been using to design my own house remodel for rendering and it works great.

I will say, I understand Juan's comment about 'open room' -- Is their a utility reason for the room being so sparse? Without much context it's hard to say. But from a completely laymans point of view (I'm not a designer or architect) the room 'feels' like it's missing something from the middle of it. Those people that can look over the railing down into the room, if the room is empty they just see a checkered floor. You could add a raised planting space (not even sure what it's called) -- by the space it looks like it could fit a 4'x8' type area that even offers a small ledge to sit, even if it was only 18" or high or so it would help break up the room flow.

P-