Right now it's just a little too confusing trying to hunt down forum topics to find the most up-to-date methods of doing things and any required files. These methods also depend greatly on minor details that people always overlook.
It would have to know what type of platform you're using (AMD/Intel/NV/ATI) and also what distribution you're running along.
So for example, apt-get install nvidia might prompt you for your graphics card device ID and, if possible, automatically install or at least tell you what your options are (EFI, standalone injector, modified KEXT's, etc)
It would also be very helpful for doing OS updates. Also for installing OSX86 utils (kexthelper, efi studio, etc)
Anyway I suppose it hasn't been done for the same reason I won't do it, it's time consuming and really only solves problems for people who can't be bothered to read & follow instructions. Still, it's a good idea for someone to work on since it's pretty easy to pull off.