I would like to see the ability to have "empty fill" or "air space" actually appear that way. Then the rafters (as I have them placed above) would not be blocked from view by the empty cavity. That actually seems logical to me... but it's Friday.
The ultimate would to be able to adjust the individual parts of a composite just like you adjust the "grouped" composite. Then you could have all sorts of fun with roofs. You could easily make open rafter tails with the decking extending past the rafter ends. Just pull the cavity in from the overhang via an enhanced pet pallet. Would be even better if we could easily modify the rafter tails other than the few options we now have. I would like to take a 2x10 rafter (needed for a vaulted insulated space) and change the tail to a 2x6 profile. That take separate roofs now and then you get shingles not displaying right... extra lines in the rendering.
As it is now to have open rafter tails you would need (in my example above) to select all roofs (after creating the rafters) and replace them with a composite without the empty cavity fill and raise all the roofs... which is actually easy and fast, but a work around.
Just read your core question... I tried it and no, that does not change it.