I have not read this entire thread so i might be reiterating some things that are old.
As far as I know and have posted in the past the RO2 zoom is quite ok if you take the average viewing distance and average monitor (based on steam survey) from the time RO2 was released.
Which was I believe a 19 or 20 inch monitor at around 50cm distance. I can't be bothered to do the calculation and check if that is correct but it's somewhere around there.
TWI didn't calculate it using math's which would be easier but they actually did a field measurement of how large someone is at monitor distance, and then tweaked the number till it matched on their office monitors.
That aside personally my quirk with fov zoom is something else.
When you zoom in your field of view becomes very small, this makes you less aware of your surroundings. (You can see further so enemies can see you at further distances, but unless you zoom in you don't see them, which makes gameplay feel quite similar to "sniper only" servers in RO1 or other games (infact the zoomed fov is quite close to the sniperscope zoom in a lot of "standard" fps games).
You can only zoom when you are sitting still in RO2 instead of when you are running etc.
Now while indeed when you focus on something, your angle of focus is only about 5-10 degrees. And when you are moving its more difficult to focus on objects. However just like in real life in videogames for the actual computer users these effects happen as well. (when you move, objects on your screen move making it more difficult to focus + headbob, and the eyes of the computer user can only focus on a 5-10 degree part on the screen).
This to me makes the inability to zoom while for instance running, add more disadvantages to moving than those that are already present. In a game where you try to resolve a battle in 30 minutes, that in real life often takes multiple days or weeks, any additional punishments on trying to move forward to me seem dentrimental to the gameplay.
Finally while i know that a lot of people disagree with me on this one. Personally in general i like a game more, when it is more about a challenge between me and the enemy. In a lot of old games including RO1, the indivdual player shadowing relative to the surroundings was broken.
This meant that players pretty much always lit up like a christmas tree, making me able to distinguish even a single pixel as a player.
Correct player shadowing, and heavy visual effects such as fog, depth of field etc. Make it a lot more difficult to distinguish a player from the background. This when put together with the lower resolution of a computer screen compared to what your eye can see makes you unable to spot enemies at a distance closer to real life.
For this reason often in more modern games, players are shown as gigantic bulky objects (A. with a mouse and even more so a controller your ability to control your muscles is not as good as in real life, B. you have more issues distinguishing objects on screen).
With realism games the solution is usually found in adding zoom. In general no matter what if you want players to behave realistic, through simulated ends (computergame). You have to make decisions to balance things out.
My personal feeling on this is simply, that in the end I dislike the gameplay effects that zoom provides. Personally i like to have as little of an interface between me and the game, as such that my game character becomes as an extension of my arm. Thats why i enjoyed the old brainless arena shooters of the past like unreal and quake, I especially enjoyed the instagib versions. And with my interest in ww2 history and teamwork objective based gameplay RO provided it was my all time favourite game.
I really wish games would not just model real life effects ingame, but model more that things that are natural to do in real life become natural ingame. Including the ability to use things like muscle memory etc.