Disney's had that for years (not a balcony - but a virtual port hole).
I will pay a premium for Donald to go scuba diving past my window or watch Aladdin fly by on his magic carpet, or tinkerbell ....) but I would not pay a premium for this on Royal. Unless it came with a dreamworks package that my kids would enjoy.
We actually like the "darkness" of an inside cabin - so I could see us keeping the curtain closed on this screen. Give me a real balcony or let me have my inside cabin. I hope the rates for insides don't go up because of this.