In the Single Engine Lineup thread the discussion of brake balance came up. The problem is that in real life, the most common configuration is vented front/solid rear, while in-game vented front and rear is almost always the best choice. I think I finally understand why this is. Currently, brake sizing influences two separate things directly: brake balance, and brake fade. In order to have good balance, you need large front discs and small rear discs, and with both brakes vented, this works fine with no fade. But if you have small solid rear discs, then you get lots of brake fade. Conversely, if you use large solid rear discs (as in real life), then you can eliminate fade, but the balance gets thrown off.
To improve realism, I propose this: add a third slider to the brakes, which only controls brake force without affecting fade. Disc size and pad type would control the maximum braking force, while this slider would allow you to fine tune front and rear brake force for optimum balance. So, for realism, you would use large vented front discs, and large solid rear discs, then lower the rear brake force until it is well balanced.