They won't fix the shadows, the reason the shadows are like that is down to the performance of the PS3, they can only go so far with it before the FPS start to drop too much.
AI - That isnt a bug, it's simply the way the AI are balanced, they could make the AI harder. Thing is though to the GTP average member, who is a good player and a good racer the AI might be too easy, but to the average non simracer joe the AI may be just right, or too hard.
Im amazed at how many complained on the TDU2 forums about that game being too hard, where as i found it a bit too easy. You cant balance it for everyone.
As for actual bugs, then i doubt all of them will be fixed, but GT5 is already a fairly well polished game, so i think they're already doing a great job with supporting this game, the latest patch is testiment to that.