The old ReportingCompatibility Module includes a very useful Cohort Builder feature.
We need to build a replacement for that feature, in the newer Reporting Module so that people can access the same cohort queries on-the-fly as they use in reports.
This project should take an iterative approach, adding functionality piece by piece. One possible ordering of features would be:
The "Cohort Builder Replacement" tickets in JIRA propose another possible ordering of features.
Here are some initial mockups that show a general idea of how this could work, but come nowhere near defining requirements.
The minimal first pass at this would be: