A symmetry tool would be so helpful. Especially when I try to draw front profile I have problems with jaw line and shoulders. Also what I would like to see in Harmony is a shape tool.
For symmetry you may find some relief using cut, copy, paste, rotate, and flip variables.
There is a shape tool for ellipses and squares but something with numerical and smoothing input would be useful for precision and to dial in stars, triangles and rounded corners.