It could be interesting to use
tips & tricks and
faq namespaces to compare what you have in mind as topics as well as format (structurized doc)
For examples dedicated to one plugin or documentation hosted outside DokuWiki, imho most developers would be pleased to see their doc inside the plugin page and HowTo in the namespace plugin ( a separate page), and in case of HowTo using multiple plugins, a link to a HowTo page..., some impressions waiting for feedback from the site maintainers.
I am doing some translation in French to keep up to date main topics (config,..) and have translated Struct, Bureaucracy and Pagemod 's documentation pages which was a way to learn how to use them.
there is already some topics :-)
namespace templates and Replacement patterns
contact form (mail)
form to populate pages
form to agregate infos in the same page e.g. "Generate Meeting protocols with bureaucracy & pagemod automatically"
form to display infos on a map
Manage a database with Struct in DokuWiki
automated document creation (PDF / ODT)