The announcement of the upcoming expansion does indeed change things a bit. For one, it means I have to consider what this does to my release schedule. I have to juggle the pros and cons of delaying production on Crusaders of Shalihir a bit to incorperate the new features of SoZ (Such as the Overland Map and assorted Chult Jungle apparel.
I can see pros and cons to both sides of this one. If I treat this like Ruins of Kazatharis, then I release it just before the release of the expansion pack to give those who don't have the expansion yet something to do. I could also treat it like Beneath the Hearleforne which was tailored around the material contained within the expansion.
One of my biggest concerns is hak compatibility and what may be effected by the expansion. That is the one driving force in my head that tells me to hold off until all the cards are on the table.
If I had to guess (I honestly haven't looked into this one yet), I would put SoZ release late fall/holiday shopping time. Which really wouldn't shift back production that much. I could continue to work on Crusaders of Shalihir, touch-up/test/verify post-expansion, then get to work on part IV (which has already undergone some script changes due to this news).
I'm thinking that may be the best way to go.
Sands of Solvheil Series
Design Document for Sands of Solvheil I: The Ruins of Kazatharis
Design Document for Sands of Solvheil II: Beneath the Hearleforne
Design Document for Sands of Solvheil III: Crusaders of Shalihir