Steve,
IMO, what's cutting down participation is the tight shooting date window...namely just 7 days. When I joined several years ago, there was no date window as to when our shots were actually taken, and the participation was high . Shooting in the 7 day time frame was encouraged, but not mandatory. In other words, entries need to be submitted in that 7 day window, but they did not have to be physically photographed within that same time frame.
Then you changed it to mandatory, and the participation dropped dramatically. That,s understandable for certain topics, like holidays and current events. But other times, it's a pain in the rear. The date window should vary. For example, I Just finished shooting a bunch of nature panoramas and architectural cityscapes in San Francisco just days before you started the City contest. I was locked out by the 7 day constraint. I was in no mood to do it again just to satisfy a well intentioned, but sometimes arbitrary entry rule that mandates that pics be taken only within a strict past 7 days.
There should be several date windows. I.E.: Pics from past Several weeks;. Pics taken within past 6 months; pics taken within past year, or current year;. Then every so often, maybe evey three months, or whatever, pics taken at any time in one's life.
The first contest date time frames were too loose, and people , even I, would not always go out and shoot. We would look for past killer content that might win. But, the current 7 day constraint is often way too tight.
A mix of both is needed.
( I have no interest or time to administer the contest. I enjoy participating.)
One final point is the contests do not always need to be limited to just 7 days. That's not always enough time. We all have different schedules. There could be 7 day contests, but also 14 day (or slightly more) throughout the year. 7 days could be standard, but longer entry submission time frames might also encourage robust participation at certain times during the year.
Hope that provides some useful feedback while you figure out how to continue, stop, or transition the WPC.
Thanks for all the work you do.
Ed