How is the improved exactly? I mean the only real improvement I see is the AI will move into the toe/draft and even if you break the toe they'll adjust to get back into it. Which I think one of the final GT5 patches did this too but I could be wrong. The problem with the GT-R video is that unlike other AI, it doesn't take any chances of adjusting the line it takes or braking zones to pass a player that could have been easy to beat. The player had awful brake points and couldn't get the car to the apex. Also what worries me is in the end of the video, the AI gives back the position and slows down like we saw too much of in GT5.
The Vette video was much of the same, hell he did an outside pass and the Z06 never made an attempt to get back the position but instead followed close.