-Restrictor plates as an option for ALL cars.
-Penalize overrewing. (Engine damage that requires a pit stop?)
-OEM/Aftermarket Brake Discs.
-OEM/Aftermarket Brake Pads and Calipers.
-More options during Pit Stops. Ride hights, Spring rates, Camber etc. (When racing in a weather race, it's just not good enough to not be able to set up your car during a pit. Something like a menu where you choose if you want to make "advanced adjustments" added to the fuel/tyre options when entering the pits. If that requres extra time, so be it, but the option needs to be there.
-A much better tyre modelling. I'd like to see the ability to fit the car with other tyre dimesntions than OEM. I.e adding 265's to the front of a M3 CSL from the stock 235's.
And have the latteral g-forces to be calculated more accurate. Not just a simple grip multiplyer as is now.
-Tyre blistering. (Caused by overheating road tyres. Big chunks of rubber start falling off the tyre and it's like driving on clay'ish tyres.)
-FULL control over lights.. Turn indikators, headlights, full beam, fog lights (front and rear when option on the car irl).
-Ability to mount extra full beam lights on the car, and place them where you want, or at least have a few reasonable options. Like grill, roof or down below the licence plate.
-As an addition to the tyno and wind tunnel, I'd like a scale where you can see exactly how much the car weights with no fluids, all the way up to all fluids in car + driver.
-More exact ballast position editor. Like if your car is not entirely balanced with the driver in it, the ability to adjust for that with ballast. Like not only the option to move the weight forward or backwards, but to the sides as well.
I think some of these are already on the list. Ignore those if so.