It's gonna be better than GTS, but never in a million years it will be on the level of iRacing/rFactor/ACC/RRRE. Complete realism has never been PD's goal, despite the game's slogan. And honestly, over the years I've learned to be OK with that because GT also does a lot of other things better than the hardcore sims. Just need to improve the FFB (and partner Fanatec instead of Failmaster), improve the tyre's longitudinal grip and account for underbody downforce. That will solve a lot of the weird physics issues with the game currently. Also make the default setup for each car reasonable. No more ARB 7/4 and +0.60 rear toe for all cars.
As others have said, I'd rather they focus on the competition aspects: BOP, more balanced cars/tracks, penalty, draft, points system, etc.