Having some alternative views/layouts for posts could be nice, like what WordPress has. Essentially templates based on post type.
The feature could allow posts in certain categories (or other criteria), or category pages themselves, to have unique layouts/templates other than the default.
Plugin authors could then publish alternative layouts.
The only issue is they might not fit with an overall theme. Eh well, win some lose some.
The use cases could be interesting: for example a category page for geolocated posts could be a map instead of a list of posts.
WordPress started as being for āblogsā but the flexibility really makes it usable for just about anything. So likewise with a few more similar features as custom post templates, Discourse could be molded more easily for unique purposes.