User blog comment:Trolypac/Categories/@comment-961279-20140803180113/@comment-961279-20141001143651

We would have to re-write the wiki's code in order to do what you're asking. We don't have access to do that and it would have to be cleared with Wikia to make the modifications.

Based on that, I'd say that as long as the people who use the letter categories are willing to maintain them, they can stay. They're taking up just a tiny bit of space in the category list at the bottom of the page and you may not even notice them unless you're reading the categories carefully.