l/''xx'' templates

The lack of features is the point, though. That's why they are fast. They are optimised for one purpose and nothing else. If you really want to get rid of those templates, I think you need to convince more people than just me. Grease pit would be a good place to go.

I know, but I don't want them to be removed/deprecated at the moment, but to remove that section that you added in l's docs which says "l/xx is strongly preferred".

I suppose if {{l}} is now faster than it is before, it is not as strongly preferred anymore.

Considering all this, do you agree that we should stop categorising every time someone uses {{l|xx|foo}} where {{l/xx}} exists?

Yes, but I think that has already changed with {{l}}'s code being completely replaced by a module. It just takes a while to empty out the category.