OP here.
I spoke with the service manager at the end of the flight. He seemed genuinely understanding and said that he would have unlocked my shade had I asked. I also acknowledged, to him, that I understood that it would always be impossible to please everyone. He claimed it was company policy, but then a couple minutes later seemed to indicate he knew that different crews might do things different ways. I suggested the "set it but don't lock people out" method, for what that's worth.
I like the 787, and the tinting window shades are a neat feature (gimmick?), but the potential loss of control with regard to the window makes me reconsider whether it's the best choice on particularly scenic routes.
I should note that on this particular flight, the shades remained darkened even during:
- Night time flying, when all it prevented was stargazing, and
- During most of the final meal service, during which time the crew turned on cabin lighting and nearly everyone was awake and eating.