I think the biggest news concerning GT6, even if it isn't official yet I think, is that GT6 will be a PS4 title.
"OMG they just hit import from GT5 to GT6 on all the cars. "
GT5 cars will probably look fine in GT6. As Gingertom said, it's the standards that need to go.
Sounds. The sounds must be improved, the ones from GT5 all sound like a vacuum cleaner.
They need to stop recording in a hermetically sealed vault.
Instead of dropping the standard cars, how about making premium versions to replace them? A little trimming would be good. We don't really need four versions of 17hp Fiat 500s in the game. Just one version, and then an X1/9, for example.