When I did my survey of communities a month ago, I noted a small number with no description. That should probably change.
If we rely on community descriptions for other functions, then it's important, maybe imperative, to have useful, fleshed-out descriptions. So I'm proposing a few initial changes, and hoping that there can be some useful discussion around other possibilities.
First, prevent descriptions from being blank.
Second, maybe set a minimum character count.
Third, ask people to name some broader related categories. Note: not 'choose' categories, as from the site list; but list some words that can be searched on.
Fourth, ask people to give some background as to why they created the community, what they hope for. It's the kind of thing that would go into an introductory post.