While playing the game I noticed that the FOV in ArmA 3 seems to be a little bit wider than ArmA 2, it could just be my eye's though. Now normally you have the zoom in option which narrows your FOV, but sometimes it's just a bit too much for scanning around.
I've used TrackIR with ArmA 2 and know that you can selectively zoom in how far you want with your head. What I was thinking was adding a way to change your default FOV from within the game as well as adding the ability to bind certain FOV's to keys in order to mimic the functionality of TrackIR for non TrackIR users.