Unfortunately, it is only in O2 that you will be able to modify what you want.
In a soldier model, there is a memory lod, and in this memory lod there is a vertice named "pilot" , that's the point of vision for the player :
BIS put it like this probably to adjust with their cargo/driver/pilot/gunner positions in vehicles, if you lower this vertice to be near the actual eye position, you may notice some vehicles cockpits may become impractical to use, not enough view of the windshield, etc..
In such case you would then have to adjust those cargo/driver/pilot/gunner animations that may be affected to refit a better view .
In short, that's more work than it seems if moving the point of view impact badly vehicle interior view.
And moving the vertice would need to be done for every soldier model you would want to play as yourself
@Sanctuary you for quick and informative reply.
First of all thank you for letting me know that it is possible
I do realize this is not an easy task, or the work you could completed during weekend.
@cargo/driver/pilot/gunner animations and positions in vehicles... I understand it is possible, although requires a lot of work.
Could you please specify about moving vertice for every soldier? It is obviuos that SpecOps soldier is different from Officer. How about the example of LAW soldier and machingunner? Would I have to change position of vertices for them separately too?
In that case creating a single custom soldier something similar to Itweas Ninja (similar in configuration) might be a solution