This request is from a PKP|PS client.
They have a journal that only allows reviewers to complete 3-4 reviews per year. They wonder if it would be possible to implement a feature that would allow a journal to set a limit on the number of reviewers a single reviewer can complete within a given timeframe.
A related option (not from the client’s request) could be for editors to be able to see when a reviewer last submitted a review, so they can make an informed decision when inviting them again to make sure they are not overburdening (and overusing) the same reviewer(s).