I find myself starting and ending the measure tool very often because it is trumps other commands. It would be nice if it was not only available while running other commands, think constraint, but perhaps always available as a dockable object.
I can remember in the old ACAD days that you could handily interrupt commands with a ', for example 'di will allow measurement while running another command. Further, there's no reason that it shouldn't be running all the time similar to coordinate systems in ACAD, the cursor location is always available in the lower toolbar. Perhaps the Inventor version would continuously measure as the user clicks along. This could include a sticky measure method, angle/loop etc.