Most reports are built to satisfy a specific need for a user. And since reports are often a first foray into hacking Gramps, they generally start simplistic in design with few options. The options that tend to be targeted first are things that CANNOT be done with a simple workaround… like a filtered export.
That’s why filters tend to be bolted on later.
It seems like documenting how to add a filter option to an existing report would be a lovely expansion page to the “Adapt a built-in Report” wiki article. Right now, it is just an un-validated shell about about how to properly fork a built-in report so that you can experiment.
But an article about how to add a filter option would make it a USEFUL set of documentation. (Started the “example of a gramplet with a custom filter configuration option” topic Sep 2024) And along with adding a Sorting option article, it might get a some people playing with improving our reports.
Both articles are beyond my Python experience levels.