‘Somehow reused’? I wonder how!
I wonder if a few too many projects are being added. Maybe it’s better to limit the number of ‘non urgent’ projects sitting in the background so that the OSM contributors aren’t quite so dispersed as they are now– it makes for lots of projects not being completed as opposed to a few being 100% done. Currently it is pretty much me alone trying to finish off Project 727! http://tasks.hotosm.org/project/727#
I totally agree with Tom’s last paragraph, above. I think the biggest issue is the lack of tools for easily visualising what edits have actually been done. This, along with a few well-thought out extra warnings in iD etc, would make the whole problem that much more manageable (and therefore less of a problem).
Some beautifully mapped areas in your list, well done :)