Not that WotC would likely release this info, but people can buy the adventure separately on D&DB, right? If so, at least WotC would know if there seems to be a significant difference betwen interest in teh adventure and the setting info or just the monsters.I wish there was some way to split Spelljammer the campaign setting data from the Light or Xarysis adventure to see how the adventure portion was received.
Though it is still a shock how well Spelljammer itself sold, despite how thin its content was.
The fact that they did not change plans for Planescape suggests they are happy with how the format has worked out with Spelljammer, or perhaps just willing to give it another shot.