It doesn't look good, T10 has banned the replays from being shown, claiming that right now they have graphical problems with them, this user says that they are a complete disaster, worse than Forza 2 on Xbox 360. It also talks about very bad artificial intelligence, it is usually a quite critical user.
The video is in spanish
He prior says that T10 has told him there are improvements to the AI for the final game.
Regarding the preview build, as you say, it is quite critical as it generally is for all games. In fact, his final sentence is:
"Even so, the AI that we have tested in this FM build is not as bad as the GT7 AI..... although that is not the best mirror that anyone should look at..."
This way people can get an idea of their critical level in terms of rivals' AI.
Then, I worried about the situation of the replays. Seeing some comments from previews, gameplay scenes and camera cuts, it would seem that a step would had been taken. They have technical space to offer replays that are worth seeing since these could be at 30fps and 4K DRS and loaded with effects and television shots.
Nobody expects excellence from PD replays for their GTs, but it is time for T10 to get serious in that aspect because it is one of the aspects that most attracts the attention of casual people, it highlights the work in graphics and visuals and is an incentive for the player himself.
We will have to wait until the final game to know this aspect unfortunately...