aye, hax...to put back in what a mod removed from the original game

not having a crosshair is fine for guns with normal ironsights, but when it comes to something with powerful optics you have a choice of:
 
1) a wild "from the hip" shot from an admittedly probably powerful rifle, but probably with a slow reload/rate of fire

or

2) very accurate aiming, but sadly optimised for a range of about 500 metres leaving you to hopelessly track with your mouse until you can finally identify that, yes, that is an extreme close-up of the guy who has had ample opportunity to empty half a clip into you (besides which each time he hit you, you were wildly knocked off-target by about 30 degrees, causing even more frantic scrolling of the mouse)

Also having no cross-hair in a helicopter when armed with 46 80mm unguided rockets makes for some fairly damn dangerous "speculative shooting" to "get your eye in" when trying to support mates in an assault (that said it can be very amusing from the cockpit..   )