The QuickCapture interface would be very useful in updating existing data. I have seen the workaround of post-processing using a spatial join to join the new data to the existing and update attributes that way, but that is a complicated method and relies on a good GPS position to make sure you are collecting the new point close enough to the old point's location for the join to work. While I am not sure how this would work directly in QuickCapture, I do think having the ability to edit existing data would be beneficial.
