Yamauchi confirms that his team at Polyphony Digital is working to implement mechanical -- not just cosmetic -- damage in GT5 sometime in early December. Less time-consuming fixes include nixing the game's odd-looking "blocky" shadows, adding more online functionality (the lounge is mentioned) and possibly offering the option to disable the HUD overlay. Work to support Logitech's G25 and G27 racing wheels in still underway, he adds.
As for what we won't be seeing, it sounds like face-tracking in GT mode and YouTube uploading of replays are out due to memory constraints. We'll also never get a chance to experience the cut "free roam" mode, in which players would have been able to drive around the gameworld, obeying traffic laws and stopping to get out of their cars to explore on foot. We imagine this was referred to internally as the "We Need Another Year of Development Time" mode.