Several modeling features are missing from the assembly level features (Weldment Preparation and Machining as well).
In order of priority please include these part modeling features in the assembly level features:
Split, Draft, Thicken/Offset, Replace Face, Sculpt, Bend Part, Loft, Coil, Emboss
* Of course these tools would be restricted to "Cut/Remove" material only. There is a bug already that the "Move Face" feature can add material to an assembly.