I think another sub-category for the Development category could be something like:
Brainstorm / Feature requests / Ideas (one of these names)
People could discuss freely their ideas and improve each others ideas an find problems with them, or the advantages they would bring to the Ubuntu MATE community
Developers could see more easily what people will want/miss in Ubuntu Mate
Also they will not be overwhelmed with feature requests spread all over the forum and they could take a look at this sub-category only if hey have time or want to implement something new