In my experience Rebrickable is by far not as Bricklink in terms of communication and cooperation. I mean, I had some contact with the 'owner' of Rebrickable a while ago and the new version of Rebrickable might even get a native exporter to LDcad's .pbg files.
Also, regarding the 'trickle down time', I don't think it's that bad. They have a reasonable amount of admins and when you inform them of a missing LDraw number (or color, or Bricklink number or any other number for that matter), it's often added within 24 hours.
Also, regarding the 'trickle down time', I don't think it's that bad. They have a reasonable amount of admins and when you inform them of a missing LDraw number (or color, or Bricklink number or any other number for that matter), it's often added within 24 hours.