There are various lists of requested pictures [1][2], but these are hidden away from the average user and so they are of limited use. Many of the requests involve a specific location, and could be surfaced based on that: when a user finishes an upload process, UploadWizard could show a call to action with image requests in the close proximity of either the uploader himself, or the uploaded image.
This would require transforming the image requests into some sort of machine-readable format; this would be a lot of work, but in some specific cases it is already done, for example Wiki Loves Monuments contests have their own database and API and could easily produce lists of locations with few or no pictures.
(This is a potential OPW project: https://www.mediawiki.org/wiki/Outreach_Program_for_Women/Round_7#UploadWizard:_OSM_map_embedding )
[1] https://commons.wikimedia.org/wiki/Commons%3APicture_requests
[2] https://en.wikipedia.org/wiki/Wikipedia:Requested_pictures
Version: unspecified
Severity: enhancement