I would like to propose the ability to add parameters to category declaration
(similar to templates).

The only major reason (IMHO) why lists are still being actively used, causing
countless hours to be spent on manually editing each list, is because categories
do not contain extra information.

For example, there can be Actors list and Actors category. Actors list would
have nicely formatted names, such as "First LastName, (date of birth - death),
Short description". Category would only list "First LastName", and might
contain some general information (at the top of the page).

Proposal: To be able to create categories with named parameters. For example:
In an some actor's article, inserting
[[Category:Actors|Birth=...|Death=...|ShortDescription=...]]

Results in a properly formed item on the Category:Actors page, with
birth/death/short description next to the name. We can have some standardized
formating element on the category page, describing how category parameters
should be rendered:
{{Render:* ({{{Birth}}} - {{{Death}}}), {{{ShortDescription}}} }} -- here, *
means the name of the article.

Version: unspecified
Severity: enhancement