@Brukanator
Handlings can be tweaked so full brake force doesn't lock the wheels (disable ABS to verify, can be hard to tell otherwise).
The downside is that your braking performance is reduced, but that's just something you have to live with if you're using a keyboard.
Alternatively it might be possible to write a script that modulates throttle/brake input and smoothen it like the steering, but nobody's put the effort in to do that yet.