At Buller, (no doubt by design), the DH tracks really don't impact the ski runs. It's through tight tree sections, and where it crosses over the ski runs, its essentially off camber transitions to the other side. At the bottom of international, there's a couple of dirt mounds off the side, used as bike jumps, but I don't even think this part is used as a ski run? Can't be sure, haven't boarded there in 15+ years.
Either way, its a shit situation, and the Mountain is going to die a quick death if its's relying on the snow season to support it.