It's like Sonny said - use the stockholder benefit for non-balcony cabins, use your diamond benefit for balconies, and frankly I'd forget about booking a Next Cruise while aboard. It is meaningless to me now.
Of course they could also take away the stockholder benefit too.
We still hear rumors that RCI is going to revamp the C&A program and do more for D+, and also perhaps make Diamond harder to attain (as in needing more points). We'll see. I just hope they grandfather those of us who are already at the diamond level.