I've thought myself into a connundrum which I'm sure has a really easy explanation that I'm overlooking.

Why does the size of the rotor matter so much for IT discussion and classification?

Aren't the brakes ability to quickly and efficiently stop the car a function of available traction of the tires. (ie threshold braking). If two cars are running the same Hoosier rs304's, and have similar weights, won't both lock (skid) at similar thresholds regardless of swept area size?

Sorry for being brain dead on this one!
R