Hi Artpen,
I agree, have been using SU a lot more for my Architectural CAD projects, I therefore fully support your:-
2. Basic building elements - (Walls, Slabs, Curtain Walls, Roofs, Windows/Doors) with use of Dynamic Components, so user can edit individual elements and create custom elements.… 
However, SU HQ seem to want to let people develop “EXTENSIONS” to facilitate certain disciplines to cater for these such items. Of late I’ve noticed some extensions in this regard cost more than SU-Pro, that seems odd to me.
I do wonder though if this thinking limits the future of SU & subsequent yearly updates & relies too much on third party extensions. Personally I would like to see SU-HQ develop some in-house specific industry discipline “ADD-ON’s” to cater for people in these industries they list on the SU Home page under:-
3D for…
In essence, this covers, Architecture, Construction, Engineering & so on.
My thinking on this would be add on separate packs one could buy. This would include various items, such as you mention:-
CONSTRUCTION PACK = Walls, Slabs, Curtain Walls, Roofs, Windows/Doors etc.
I can see a deeper future in this direction may be, just a thought.
Over & out,
Clayton.