Agreed, I've been saying it from day one. The rear traction on the players car is catastrophic in all configurations. Even with the on throttle differential on 10 it's pretty useless compared to the AI traction.
The principle issue for me is you need to have two separate AI levels to be able to compete from a realistic perspective.
I have to reduce the AI level by -5 to -10 from what I would normally race at in the dry.
With full TC on using a pad, the rear of the car just doesn't grip as it should especially when you directly compare it to previous itterations of the game.
In all honesty although I am enjoying it more now in the wet, due to several factors, mainly changing the way I set up the car and the minor changes made in the patch, it still remains a massive oversight by the development team. And something they absolutely can not repeat for F126!