Couple of reasons I don't like this:
1) It's another weapon type. Wherever possible, existing weapon types should be used. A Vlaunch missile with a very high trajectory and homing would have many of the same powers thereof.
2) The defense list in ZK is already very long, particularly mid-priced land-based defenses.
3) It's counterintuitive... players want to be able to see what shot them. The Sharpshooter justifies the fact that you can't see the firer because that's the entire
point of the unit.
That said, I do see the need for some kind of anti-scout defense that handles the problem of enemy units that invade into the interior of your territory. LLTs and MTs fail hard when you get a Custodian or the Factory blocking their shot, and the scout/raider game is
vicious to newbs for this reason. Having some way to say "I suck, I don't think I can clear an invader out from my eco" at the very beginning would be handy. Building solars instead of windgens helps, but it isn't enough.
But I'd rather see if there was some way to make this happen
without adding yet-another-defense. Is there any way we could make an existing defense get this ability? Like modifying MTs to fire at a raised angle?