A suggestion from the peanut gallery...

1) All future releases have default.svg with the display units set for px, scale= 1uu/px

2) Move the scale controls to another tab in the Document Properties panel, with language to describe function.

3) Expose the "Set page to drawing or selection" toolset (which is often overlooked by new and veteran users) on the Page tab of the Document properties panel.

Mockup of modified Document properties panel:

(also attached in case this board allows)

The above changes should alleviate most of the confusion and retain the controls for scale. Typical users needn't be concerned with scale and its complicated workings.

Thank you for your time and consideration,

TD