The range on the heavy sniper has recently been reduced. Definitely can't snipe from as far as away as previously.
its range is still somewhat the same from my experience, when i was testing it earlier i managed to snipe a guy out of a tank on the edge of the vehicle render distance
maybe the render distance for vehicles is the only thing thats changed
I've definitely noticed a change.
the sniper range was reduced on patch 1.09.
used to snipe people on foot from huge distances, now they pretty much keep a 1 block distance and be safe from the sniper.
you can still snipe someone if you can't see them.
i do exactly what the op hates. i shoot at every heli/plane/jet/car/truck/person that comes in range.
usually after the heil starts smoking they either land it on a building or bail out. if they bail and i can see them i'll snipe them out of their shoot. if they land on a building, i'll keep shooting the heli until it blows. if the explosion does not kill them i will use "searching shots" to locate and kill them. i just keep shooting every inch of where i think they are until my scope flashes red and i kill them. it works about 70% of the time. (another good tip is looking for muzzle flashes from other peoples guns when/if they fire them.)
TLDR, spray and pray works well.