Not going into discussion about the problems inherent with over-categorizing I’m wondering if a petition might help?
That is, areas of Discourse have been “virtual DOM-ized”
AFAICT making the change is not trivial and requires rounds of patching and polishing.
But it has been done when doing so resulted in very substantial performance improvements.
That is, it was worth doing.
AFAIK the Categories list page does not have a performance issue.
Being VDOM allows for different sections of the DOM to be worked with via “widgets”
I think if other areas of Discourse, such as the Category page could be “widget friendly” it could help.
Even if not fully widgetized, if there was (is?) a way for plugins to get a foot-in-the-door it would be a lot better than over-riding templates.