As I understand it, [v]'s turret code is one of the worst areas of the whole FS2 codebase. I seem to recall someone saying it's amazing it works at all, and I'm pretty sure multiple coders have tried to clean it up, but it keeps breaking on them.
If it's going to be done, I think the whole lot of it will have to be redone, yet its behaviour would need to be kept very close or identical to the existing one. Add to this the fact that there really wouldn't be great things to gain from it (unlike with things such as the HTL engine, scripting and multiple dockpoints and the rest) - side multiparts, turret recoil (which you can now do via scripting anyway) and maybe better bomber turret handling are probably the most significant things.
Considering that, I can easily see why taking on that massive amount of work for so little gain isn't a popular idea among coders when they have much more helpful projects already underway.
