I had the same concern as you so we chose a AD category minisuite on the Emerald Deck (we're sailing on the Grand on 7/29). We wanted the larger space that the minisuite provides but we were really concerned about the lack of privacy on the balcony from above. I think going with the AD will give us what we want because the balcony appears to be private from above and we get more room inside than a BC category room has.
Anyone else stayed in an AD stateroom on the Grand? I'd love to hear your comments.