I doubt Cyan ever intended to open up the tree area in MOUL, it would take way too much reworking after the reworking they already did for the PotS ages to work in MOUL. With their small group I would think they needed to work more on puzzles that could be replayed, not public ones. But maybe I only think that because at the time before the announced cancellation I was really hoping they were focusing on getting Kahlo in game in some form and that they were done with just converting stuff we had already seen in CC to MOUL... If anything it would be nice if Open Source could somehow lead to see the ages we never got at all in Uru...
But, it is clear they had very different plans at some point long before MOUL and PotS, when they were much more... well staffed. PotS areas especially getting big changes. I wish I could still find some of the really old screenshots I saw of areas like Ahnonay and Negilahn from earlier development stages
A small thing I find interesting is The Watcher's Pub is missing two wall imagers (like the ones with a visitor list and the ones you can put pictures on in Bevin). You can actually "feel" the solid meshes for the imagers still in game if you run at the spots on the wall on both sides of the main doorway that you link-in in front of.
If you play CC, and look carefully at the link panel for the CC Watcher's Pub you can actually make out the wall imager in the linking panel picture.
See it in the red circle?
Then again, you also can see a Nexus book on the Nexus stand in the link picture for the Great Shaft, but I find that stuff interesting.
Also, I seem to recall a preview picture of Minkata back in the Gametap days that showed a Minkata cave, but with a weird looking device in it rather than one of the stones... so I guess those kinds of weird changes are normal in age development.