Divinity Engine will never be as simple as the Aurora Toolset. It can't be. NWN's areas in modules were tile based, that's what made it so simple to use. Click and place, click and place. Didn't matter if it was indoors or outdoors. Everything was click and place. The only thing similar is that they both have a complex scripting system that allows for so much, but that's where the similarities end more or less.
Divinity works on a much different system. The landscape is not tile based and it isn't just full of prefabs like Aurora/NWN was. That cliff you ran into in NWN is a prefab, but in Divinity it's dozens of well placed rock models to make it look like a cliff. The trees are individual, not a group of trees in a tile. There's just no comparing the two really. Divinity Engine is much more complex, and that's one of the things that's hurting it.
This is exactly what I am saying - although you explained it perfectly.
Just putting documentation will not be enough. Some serious work should be done on editor.
Creating prefabs is must, among other things. Perhaps even a mode where some kind of tile system exists.
This might be as big as a new project for Larian. But the investment would surely pay out. Even if the improved editor would be sold as DLC.
Heck I am sure if Larian puts this improved editor project on Kickstarter - They would have backing in one day.