This has been talked about a bit.
My thread on a similar thing, Destructible Vehicle Sections, is here
http://www.planetside-universe.com/s...ad.php?t=41325
Vehicles don't live to long is probably why they don't do too much on this. But I do gotta say, if they had it, it would mean that vehicles could have something disabled before being blasted down to dust.
It's always gonna be an interesting idea though, but could be difficult to add too much to it.