So, as I understand it, Shattered Dreams is basically going to update the Athar from the "we're fleeing from the Gods because we've got nowhere else to go" status that they had earlier into a genuine faction again? Also, provide a nifty adventure where the Athar actually manages to put a God on trial.
I guess a couple of questions that come to mind are...
1. What do people see happening to the Athar after this in "canon"?
2. How will these events effect Planescape canon as a whole?
I think most just want to see the Athar revitalized as a Faction, and to give them some more plot threads to follow up on.
I personally see these threads being important:
1) Tension between the militaristic and peaceful branches of the faction, possibly reflected in the physical split in the faction between those members at the Spire’s base and those still in Sigil.
2) The presence of kamerel artifacts at the base of the Spire and in Mirage, including mirror magic.
3) Possible tension between the rilmani and the Spire Athar.
4) The fact that the Sigil Athar are testing the limits of the Edict.
5) Possibly the aftereffects of the God-killing weapon.