Well, please take a look at this video.

http://www.youtube.com/watch?v=d0wqDICAgLo&feature=youtu.be

As you can see, it's almost impossible to predict if you will hit a target in first time, so it can take some time before you hit anything if you're using TrackIR and that can take a lot of time, especially if you must do a precision strike where a failure (or miss) is not an option.

Well there I have two suggestions.

1.) You make that the HUD stays on same place, so you can look around freely with TrackIR AND know where you will hit for first time. I imagined how it would look and then made it in a photoshop (it's loosely shown but it shows the focus of my idea. First picture 'how-it-is.png' shows how already it is in the game, and second 'how-it-should-be.png' it's my view of ... well, you know, how should HUD behave).

2.) You simply remove the HUD and put the crosshair back so then it looks same at is already on the AH-9 helicopter.

Well, for the conclusion - this was already annoying in ArmA 2 with AH-64D and AH.1 Lynx helicopters, and I plead you to do not the same mistake again!!!