Hi James, a few thoughts about renovation tools, composite skins and openings:
To me it would be very very useful to allow a composite skin to have a renovation status.
This way you can quickly add an insulation layer to an existing wall rather than creating a new wall, on a different layer with different layer number.. this tends to be complicated and creates conflicts.
Or quickly show that you are removing a ceiling (its skin being as downtaking the rest staying as existing) rather than drawing a slab and a ceiling, or adding a new floor to an existing slab.. I find that limiting the amount of elements drawn (sometime exactly the same on plan) is so useful.
It would seem to me a really good easy addition, those who prefer drawing several slabs on top of each other or several adjoining walls could still do it if they like it.
I'm not convinced of a workaround using complex profiles, although having the possibility to determine if an element in a complex profile is existing/to be demolished/new sounds like a good idea too.
Another thing concerning renovation tool is to make openings smarter with it.. if you put an existing opening as downtaking, then the "hole" disappears, (that's not like that in reality).
Then you need to battle with layer and priorities to show how you fill up the opening with new materials. You want to keep a smooth connection with the new filling though especially in elevation where you don't want to see the old opening line.. I guess if the external material was the same it shouldn't be a problem