I'm not convinced that this would be a desirable feature. If a numeric dimension is being obscured by its own dimension arrow, I don't think you should be forced to zoom in to read it.

There are already several things you can do to make your dimensions legible regardless of how zoomed in you are.

Much of this is explained at: bikecad.ca/dimensions_dialog.

Steps I would recommend include:

• Turn off the display of linear unit symbols. Many feel that displaying the mm or " symbol next to a dimension is redundant. Removing it will free up more space.
• Change the dimension text size. A smaller font will fit along a small dimension line better than a large font.
• Change the size of the arrow. There's an icon for this. It is described in the final seconds of the video at: bikecad.ca/dimensions_dialog.
• Rather than attempt to show a dimension value between the two points that are very close together, drag the dimension value outside of the two points being dimensioned.