Hi Lady Vidora,
We were in a BA cabin on Diamond Princess, a near-sister to Grand Princess. It was nice being on Caribe Deck as the balcony was large (10x10 sounds about right, although I didn't measure), and it was about 1/2 covered and 1/2 open. The interior was about 200 square feet, yet it was set up in such a way that we had plenty of storage for clothing. I do recommend bringing an over-the-door bag for the bathroom, though, as there wasn't a whole lot of shelf space.
The balcony was large enough to accommodate a small table and 3 chairs, two small loungers, and side table.
I have two photos of our cabin - click below:
(This was taken about 1/2-way into the cabin. Behind me, and out of view, are the bathroom and a closet with lots of hanging space. The mirror over the bed shows what is on the wall opposite the sleeping area.)