The thing is with a static hierarchical directory you get stuck with the hierachy you built. Tags, even reddit semi permanent tags, are more dynamic and finer grained. By letting a site like Reddit create the categories you help stay on top of what topics are new and fresh. It’s like suggestions coming from the grass roots rather than top-down.
So, perhaps tags (or subreddit-style categories) are good for initial categorization and then a more detailed hierarchy is good for a competent editor. I also wonder: how did you track expired links? Changed links? Would you indicate that a story got an update?
Reddit has done a similar thing with wikis. By giving each subreddit a wiki, many are able to arrange a heirarchical directory of links. I guess I’m wondering if a wiki is a suitable replacement for a directory. Or if the only difference is having a crawler attached. (Which is a formidable difference.)
An idea I’ve had with Indieweb.xyz is to have users submit a finer-grained category using the u-category class. So they could submit:
<a href="https://indieweb.xyz/en/startrek" class="u-syndication u-category"> xyz/startrek: Photos: DS9: Nog</a>
And it would place it in the permanent hierarchical directory (which crawls links to keep them fresh.) It feels like some moderation would be needed. But I am trying to stay away from that.
I appreciate your thoughtful replies. I am starting to both see how directories are present in our modern incarnation of the Web and desire some innovation for them.