I used to wonder why you don't see disc brakes more often on road bikes. Now that I have them, I know why.

The road BB7s are fine but not a revolution in braking performance, especially if your road bike is used mostly in dry weather. That said you should be able to skid the rear wheel. Cable housing is more important in rear brakes due to the longer cable run. Compressionless housing (the kind made for brakes) makes them feel a little less spongy and might help.

Rim brakes have a ton of leverage compared to discs, especially on 700c wheels. I can see though where on off-road bikes, discs would have an advantage. As tires get bigger and harder to clear, you need more massive brake hardware for effective rim brakes. Offroad bikes are also more likely to be ridden in mud and in other conditions that favor discs.