I've been thinking on it, and I believe an elegant solution to it would be to have the impact craters show direction. Basically have the higher bank on the impact crater away from the direction it was fired, and if possible have it be a longer impact crater the lower the trajectory is. Basically a long oval crater would be close, a rounder crater would be far.
It might be a teeny bit gamy, but I like that a lot better than having tracers all the way. A possible compromise (not sure if this would be easier or harder to coad) would be to have a tracer show up say 1000 yards from impact. This would also give some directional indication without saying 'ARTILLERY BATTERY HERE!'
I'd be curious to see how it worked out. I could see a well organized group of say, 4 GVs and a spotter doing a lot of damage with a couple wirbles, an artillery battery, and a tank possibly for cover.
Wiley.