On the user dashboard, along with the progress stats already provided, I would like to request that a heatmap also be displayed. This would show which days reviews were done and roughly how many were done based on the color. This would add another layer of motivation and interest to keep people engaged in the WK system.
I picture something like Bunpro displays on user stat pages, or Anki shows when the heatmap plug-in is installed:
Just a suggestion. Keep up the good work!