I am surprised that this draft hasn't gotten any response yet, since it attempts to make quite large changes to the CDB structure and usage. Here is my two cents...
My biggest concern is trying to make the Integrated models dataset do the same thing as the non-uniform elevation dataset. The Terrain Constraint Integrated Models section describe exactly what the non-uniform elevation dataset is intended to do (inserting a point or line into the terrain). And it seems that use of Integrated models will require non-uniform elevation anyway.
Creating new vertex flags gives a lot of control about what the vertices represent, but at the expense of added complexity to the CDB RTP. I would think that the easy case of 2D Integrated Models would be as easy as marking a polygon (polygon flag or XML comment) to be draped on the terrain skin. And if the terrain below the model needs to be flat, well we have the non-uniform elevation for that.
Will this dataset replace the existing GS and GT models and shapefiles? There is a lot of culture that doesn't need to be an Integrated Model, and it is much faster to process these models.
Here is our first draft for the Integrated Models, please provide us with your feedback and comments.
We will update it accordingly.