Rotor scoring (as in, grooving not unlike a 78 rpm phonograph record) to some extent, is a function of the abrasiveness of the brake pads used (in my opinion).
What brake pads have you used?
My riding partner and I installed identical oversized rotors (320 mm?); he chose Gafler Green pads (unavailable now, I understand), I installed OEM pads. After a couple of thousand miles, his rotor remained essentially smooth, while mine looked like you could stick a phonograph needle into the grooves and listen to the, "Golden Oldies" of yesteryear.
I changed to a, kinder, gentler pad; no significant compromise in my mostly-pavement riding braking, considerably smoother engagement.
The brake pad manufacturers know what they're doing: A "racing" pad (and rotor) need to last only one race; the designers are more interested in, "there's no tomorrow" competitive friction; serious racers don't mind replacing pads and rotors; longevity isn't primary interest.
The service limits for brake rotor thickness appear in service manuals; mine ain't handy to look it up. A competent machine shop, I should think, could re-surface a rotor; serviceable along as minimum thickness can be maintained. Mind the pads used after the rotor is smoothed.
All this said, I agree with posts above recommending oversize rotor and corresponding caliper bracket vs. OEM replacement; a cheaper and more effective upgrade. Might consider a steel-wrapped front brake line, while you're at it!