just a think,
see the youtube video at hard surface tool for z brush
I think it is possible with blender sculpting if the layer brush have a constant flatten brush + layer brush . So if you click on the surface and the layer don’t follow the surface curvature just flattening it than we have very same as hard surface tool.
The first picture is a simple layer brush and the second is layer brush and than make it flatten … but the result is not exact flattening of course.
some other idea would be cool if with smooth stroke have straight line if i hold down shift key.
Other question , can i use blender sculpt tool with tablet pen with support angular offset feature?