Another vote for eye shades. The blind is in the control of the occupier of the window seat.
Personally if I'd like the blind open but most other blinds are closed then I will just open it a small crack so I can see out enough. Whilst I believe it would be acceptable to have it wide open, I want to rub along with others OK too - we're all together in a confined space, so that's my idea of a compromise.
If there is direct glare onto another passenger, it is a different matter and I would be happy to close the blind until the angle of the sun has changed.