How about, instead of having the grid line up the distances on the maps, introduce a new weapon (well, not really a weapon, but a utility), the laser-rangefinder. It works sort of like a tracer-laser, but you aim it at a tank or position on the map you get the exact distance in meters.
this should make distance-counting a more a matter of wasting a shot on it or not. This could also replace tracers imho.
Oh, and it should not be possible to use this through mountains like lasers.