Elevation - The grasshopper API mentions elevation so maybe possible? Beneficial for judging how hilly a planed route would be. If we were able to see elevation profile that showed where hills are,
Strava Example - Profile at bottom
Straight line distance - When switching to straight line mode (ex: when you know a shortcut, hop a fence, etc), the straight line distance is not counted. In most instances the straight line distance is short before jumping back to snap mode but perhaps there are some that build mainly in straight line mode
Example: See the distance increase when selecting the first non-start position. Then switch to straight line and after clicks distance stays the same.