not a bad idea
one mechanic i really like though is sometimes you have to shoot at enemies you cant see, meaning you have to remember their position. the mouse currently controls aiming, and if it were to control your field of view as well, enemies that youre shooting at would ALWAYS be in view. there would still be some level of having to remember enemy positions but it wouldnt be the exact same.
alternatively, i could make it so you shoot in the direction youre moving (meaning, aiming would be tied to wasd) but that would probably lose a ton of precision, in a game that is more or less precision based
all in all i think moving the field of vision with the mouse is probably the way to go, but ill have to figure something out for the rest of the controls. ill have to mess with it more i guess
thanks for the kind words!!!