This is a feature request that would open a whole new avenue of improvements for weapon optics and their general usability for players and is one of the methods a lot of modern games use to handle '3d scopes'.
It is similar in nature to https://feedback.bistudio.com/T175562 but would allow for far better flexibility.

Current Situation:
3D Optics in arma require very specific set up to be usable. This requires the existing optic design to be a specific shape ('Straight through' optics are easier to work with) and in the view pilot lod (used in first person) the optic needs to be warped, usually in the shape of a cone to counteract the FOV change otherwise too much of the scope 'walls' will be visible for the player.

For vanillas optics, only the most observant would notice this. As a lot of tricks were done to hide the 'warped' nature of the scopes in first person.
For modded optics, only sights with Objective Lens and Ocular lens of similar size can be made 3d otherwise the actual field of view through the scope for the player will be much smaller than it should be and depending on the design, completely unusuable.

Proposed Solution:
View Gunner lod will be utilised when cameraView is 'GUNNER' (Player is aiming down sights), and View Pilot will remain used in first person. If View Gunner does not exist, View Pilot will be used as it is now.

The advantage of this over the current situation is it allows the modeller to do whatever they want to the sight in order to make it usuable by the player. Warp the shape for better vision, remove entire parts of the scope structure etc.
Scopes that would have never worked previously as 3D scopes could now be done by creative model adjustments.
This method (or thereabouts) is used by a lot of modern game engines to handle 3d scopes, usually by hiding parts of the optic in order to allow for a proper 'full' field of view through the scope.