No you nailed it. With the biggest offender being the sounds. They're still absolutely pathetic. Forza on even my tvs speakers gives me goosebumps. GT is honestly still stuck in the ps2 era - with regards to sounds, menus, and many other aspects. Replays look great, but you can't pause and reverse - making photography a royal pain in the ass.
Oh geez yes. GT5's sound design is an affront to my ears. I would rate the sound a 2 out of 10, and that's being generous. I haven't played GT6, so I couldn't say personally.