I guess it depends on the car, then. A few cars in the Goodwood special events surely to me seemed like they would have benefited from a more frontward brake bias.
Anyway, I was curious to check this out in detail with normal cars in my garage (I usually just decrease the rear brake power to 2 or 3 as I used to do in GT5) so I tried adjusting the BB on a small FF (Mitsubishi Minica Dangan ZZ) and to my surprise with 0/10 I'm unable to lock rear wheels. Actually the brake bias setting doesn't seem to be working on this car.
Checked again on a Dodge Charger 440 R/T '70. Same. The brake bias setting doesn't seem to bring any change in car behavior, no matter what values are.
So it's true, as @
super_gt hinted. The brake bias setting is not working at all. What's going on??
EDIT: actually after driving a bit with a 0/10 setting it does seem to have an effect, but it's very small. It's mostly noticeable when braking and steering at the same time, but not so hard as to lock or overload front tires.
EDIT: I tried adjusting the brake balance on a Honda S2000 and doing braking tests on Indy, and again, no matter the setting, this car just wants to slide when braking. I'm thinking the base braking behavior is now hardcoded on the car and that apparently it can't be adjusted anymore as of GT6 v1.01.