Hi @mikelmaron, thanks for the many great ideas in this post! Some of them could probably be separate feature suggestions.
Regarding this item of matching OSM-expected output with KoBo output:
Exporting only the fields you are interested in is possible, though only via the API at the moment.
The length of the response name issue is only for using the formbuilder, not when importing from XLS. So setting the response name to amenity=place_of_worship should be no problem if you design your form in XLS.
The XML question name can’t include :, but you could use the proper OSM-compatible name in another language (e.g. label::OSM) and then export your data to that language. This could also be a workaround to the previous issue.
Do you have an example on how this work at the moment and how it could be done differently?
I think this could also be handled by adding an additional ‘language’ to your form, which would allow having multiple amenity columns.
GeoJSON is already possible, though only to export points, lines, and polygons created with these question types. The entire dataset could be formatted in a way to allow importing, but we would need much more details to guide the conversion.