You're absolutely right, it actually NEVER did work.
As for the thruster thingy, this would be just one way to look at things:
Here's some more examples (as well as a problem with the current trail rendering shown on top):
clicky Of course, I'm speaking from a totally non-coding point of view here, so the whole idea of FOV checking might be total rubbish (although I guess that's more or less how the current system is handled, kinda - and it's possible as the subsystem targetting shows

). But hey, if it would work, it would certainly work (a lot) better than the current system and provide a
significant upgrade to FS2's graphics, since the thruster problem is probably the biggest problem with the current visuals we face.