Yes, that's exactly what I mean about ways that start off identical and then diverge.  I've not used an editor that adds to multiple ways simultaneously - I didn't know that there are some that can do that.  I'm certainly seeing unintended overlaps and gaps between areas.  And also linear features that clearly ought to be the delineation between areas (fences, walls, hedges, etc) getting out of sync with their respective areas.  I always understood it to be best practice to use these boundary ways to form the areas.
Having multiple ways sharing the same nodes certainly makes it very difficult to select the way you actually want to edit much of the time.