I think Minty is talking about auto-generating the list of potential filters, having a way to dynamically add/remove filters, and allowing each filter to specify which field it is filtering on. It's an interesting idea, but there's a lot of detail to flesh out.
The hard part of that is handling custom filter fields (i.e. search by spellcasting class in Pathfinder, when multiple classes embedded in Source field); deciding whether a filter should be a dropdown or a free text filter; and building the UI to support addition/removal of filters dynamically.
It's quite a task, but Minty seems to like those.
Cheers,
JPG