DT Swiss do make make centerlock XTR compatible hubs. I think other do now too. The ceterlock system is so much better than 6 bolt jobs. Even tension so the rotor is less inclined to be warpped by uneven bolt tension. Very unlikely to back off too unlike some rotor bolts. I've always used a tiny dab of locktite so I have never had a problem but I have assisted a few guys in the woods with loose rotors.
Did no one notice that the riders are RACING on XTR? Racing is about going as fast as possible. That means light is right. XTR is all about being the lightest best functioning racing parts. Turns out though that in many instances it is also more durable because they use stronger alloys, better bearings etc.
Freeriding is a different game. Saint, Diabolus Hoosa feld and stuff like that are more apropriate.
I laugh every time I read stuff like this though, the SRAM vs Shimano crap. Why? Because I rode mountainbikes in the early 80's and the stuff we rode then was equivalent to Zellers brand crap in function. I mean really, try and and get some crappy equipment today. Even low level stuff works better than what we had back in the old days.
Debate? Bikes are made for riding not pushing.