Zen

This is for feature by feature feedback.

Paint Displacement

While Paint Displacement is active and sub-dividing geometry, the Object Properties options should not disappear.

Surface Tool

While the Surface Tool is active, and you are dragging a new blue edge, there needs to be a key to unifrom scale said edge. For example dragging the middle mouse button. This will allow for better control of the topology has it is being created.

Surface Snapping

Surface snapping could use an offset along the normal in order to make edits visible above the Surface. Another option to address this would be to have a visibility mode where the selected geometry is always visbile above any other geometry.