I'm not sure why Developer mode uses fixed brightness. It would be great if it could adjust according to the phone's brightness setting. It might even help spot some issues with your game's colors, such as looking muddy at lower brightness levels.
S7 Exynos Nougat. 2017 Gear VR. Public test channel.
Yes! Gamma adjustments for each eye would be great. This is a big issue for a lot of devices including the S8 where the brightness is uneven and there is nothing wrong with the screen.
Thanks for the response. I've also filed this as a "bug" (https://developer.oculus.com/bugs/929419780541052/) on the grounds that this behavior was not intended, but also to be able to make use of the bug tracker for better visibility.
S7 Exynos Nougat. 2017 Gear VR. Public test channel.