That involves way too much CPU usage, and doesn't really add anything to gameplay in an RTS title. For an action title, sure, and stuff that shoots at you in Alden Ridge does use that sort of technique, if I recall (plants shoot these little pods). But in terms of an RTS, it's a waste of CPU and programming time.
I'm not looking to make things more complex here, or to massive reinvent the mechanics of shooting in any particular fashion. Right now it works, it's clear, it's simple, and the game is balanced properly with it. Why reinvent things to add bugs, make it more complicated to use, make things unbalanced, and worsen the performance?