Does Rotor Scoring caused by old brakepads warrant rotor replacement?

To get the best performance from your new brake pads, you either need to resurface (if the disks are thick enough) or replace the rotors. You could run them as is, but again, you'd not be getting the best performance.

My own personal preference is to replace the rotors. The reason being is simple. New rotors aren't really that expensive. If you calculate in how much time and expense it takes to take the old rotors somewhere to have them machined, along with the inconvenience of having the vehicle down while you are waiting on the machining ... having it done on your schedule is invaluable.