^^^^
i dont think Fable 2 is designed to be on PC anyways, its selling alot on Xbox 360 , the old one didnt sell well on Xbox so they decided to port it to PC.
about Gears, its up to Epic , if they wanted one they make it, im sure they saw the first one on PC didnt do well , so they will stick to X360.
and lastly halo we might see a PC release after they release a new one on X360. Maybe after ODST?