It seems as though the mere existence of a dead zone and snap-to-center feature isn’t everything for you, but I’d like to say that a gaze based snap-to-center feature (as opposed to a button) would be incredibly useful. Dead zones have already been implemented (although there is no graphical representation in ISE) so all that remains is the hands free snap-to-center, possibly configured as shown.
Forgive me if I misinterpret your feature request, but it sounds like you’d want a sticky center, such that the dead zone is enabled until you gaze at the perimeter of your screen, which is when it the dead zone is disabled, giving you full camera control until you snap it back to center based on the camera yaw/pitch coordinates approaching 0.
The dynamic dead zone would definitely be an elegant addition to it’s current state, but the snap-to-center is a must, for me. Whether that’s done by simply looking at a specified zone (as shown in the above image) or by gazing towards the default camera position (which I think is what you’ve suggested, still not sure). Just as long as I don’t have to juggle more buttons (I’m using 3 shift buttons on my HOTAS as it is.)
The only problem I’d have with the dynamic snap-to-center is when turning the camera too far, I wouldn’t want to have to stare at the perimeter of the screen until I approach center enough for it to snap into place. This wouldn’t be a snap-to-center on demand feature, it would just be affixing camera and re-enabling the dead zone. If that’s what you meant, I am requesting an actual snap-to-center feature based on gaze. Your dynamic dead zone / free camera movement wouldn’t pair well with the snap-to-center zone I’ve shown in the above image. I would be fine with it, but to allow the dynamic dead zone and snap-to-center features to coexist, I’d propose a dynamic snap-to-center zone as well.
Instead of a central snap-to-center zone, the zone would be at an edge or corner of the screen based on the current camera angle.
For example, if I look to the upper right corner of my screen, the camera breaks away from the sticky center and gives me full camera control. Since my camera is aimed to my upper right, the snap to center zone is on the lower left corner.
At this point, I can guide the camera back to center where it will stick, or I can glance towards the snap-to-center zone to center my view (especially useful when my character’s neck is contorted as he admires the all the flashy lights.)
As I mentioned in my other (redacted) feature request, I’ve attempted to use the snap-to-center button in combat, and it’s simply impractical. However, a snap-to-center zone (plus dynamic dead zone / sticky center) would solve the issues I had mentioned in that post and as far as I can tell, these features would be more useful to others than dynamic sensitivity ranges.