Hi Gareth !
glad to be here and quite impress in the middle of you all 
As you said yourself, I think GIS integration need attention I think.
Select on maps is a first significant approach I think. On a long term I imagine a map centered mode based on entity, alongside the classical mode we actually know.
For the rest, it as hard to speak for the whole community, because I "represent" only a subset of it, with its own needs and thematic field issues.
I think one transversal thing missing is a real place dedicated to final work sharing.
I realized during the workshops and courses I co-animated in the last years that potential users (coming to the workshop) only need a little kick to really start using ODK. A lot of great resources could already be found over the forum and, but deserve to be organized and exposed I think… I really don't think the actual sites (forum and docs) are not satisfying the community but I think they could be completed.
So I think the TAB could help to organize and build a kind of resources center, complementary to the documentation and forum, where users could search for a particular feature or thematic and take a form (or a piece of) and associated documentation from the shelf, or pick a R script, a SQL piece of code, API call examples, and watch great tutorials from @janna or stats4SD.
If few of ODK fans and heavy users of each "ODK Community subset" could share and document a part of their work (forms, data workflows, tutos), I am really sure this would help a lot of people to take the step to use ODK and to share best practices.
Such resources will also be an input for community discussion (Core team, TAB and users) to make ODK even better.
Presenting its own work takes time. But from my experience, its is an invest more than a waste of time. Encourage users to participate will need some animation work. The TAB could take it. I remember how your and Helene's advises and proofreading encouraged me in 2020 to write my first showcase !