Modern games (some of them) render in a way that if the resolution is wider, you gain view on the sides. Older engine do the opposite where wider views chop off the top and bottom.
It's been this way in AA since day 1, so w/e. And it's not gonna change either, it's an engine thing and it's an old game.
But it's possible to change the FOV in the game. It's possible to make better for 90% of the users who have widescreen monitor these days.
I would say it is more important to see what is going on to the left and to the right, I don't see why its important to see the floor and sky.
AA has a lot of vertical gameplay, it's not CS. Example: When you enter the main pump room in Pipeline, a tunnel vision like this means the difference between life and death.