So that abs would be like real one, on/off instead of decreasing brake pressure. TC to have ignition cut (hardlimiter to current rpm) and optionally throttle cut (softlimiter to current rpm). Oh yes and also automatic shifting help should be like realistic automatic gearshifting.
I think what is needed is to differentiate vehicle assists and driver aids. Right now abs, TC and auto shift are driver aids, they are meant to help drivers who find a car difficult to drive have an easier time. Thus they can be used if even the car you are driving lacks this feature in real life. What is needed is to add vehicle assists to cars that have them. For instance cars with automatic gear boxes need torque converter modeling, auto shift would act the same for cars with manual gears boxes as it's a driver aid (manual cars don't have torque converters). Cars that are equipped with traction control would then need true to life traction control profiles such as the ones you listed. Same goes for cars with abs. This way if in real life abs or TC or even stability control can't be disabled then you can't just toggle them as a driver aid. On my car a Mazda Protege 5/323F abs and non-abs modes very. On the abs model, a abs sensor is used to measure vehicle speed. On the non-abs models you have a gear on the transmission instead. Disabling abs by pulling the fuse will disable abs but you end up with wonky brake bias as the abs system assisted with that too. So you can add in a pull fuse upgrade to the vehicle upgrade list but on this car it would have a slight negative effect.
No speedometer if abs disabled by pulling the fuse, that would be quite nice too, such small realistic details make experience, imo Also there are some blip functions defined in PLR file which would need to be really such that mod sets how they are in real car. Little things but they do make quite large effect to experiencing realism.
