You are haven't been keeping up to date on GT6, or you knowingly posted false information in your post (which, by the way, is against the AUP). While we can be sure that they won't feature a livery editor as complex as the one in Forza, we do not yet know whether we'dd be able to do some sort of livery customization.
You have nothing to support your arguement about the AI, as Kaz has specifically said that it won't be the same. While none of us can say whether or not the AI will truely be improved, we sure as hell don't know if it won't.
Game will feature at least 1400 cars, at least 400 of which will be premium. Probably more. NASCAR's aren't duplicates, and we have no way of knwoing if they're counting the anniversary cars in their total car count. It's worth noting that 1400 is not an exact number, just like 1200 wasn't back when GT5 was released.
We have no way of knowing how many standards will be converted, and it means literally nothing that they haven't shown that many yet. They have no reason what so ever to show you everything before release.
We don't know why they didn't show up at TGS like they said they would. It could be because Kaz was busy promoting himself and his documentary, or It could simply be a change in plan. Saying it is because they have nothing to show is rubbish.