The standards for featured add-ons have simply grown higher good sir. Parts-config files don't cut it anymore in the eyes of the repository standards committee. They require fully functional and free add-ons now, of which many add-ons originating from within this community are neither.
"Fully functional" is just the bare minimum to get it approved anyway, and all repo mods are free unless demos of paid mods don't count. The standards for featured mods seem to be weird, the way I see it is that the devs choose mods that they find subjectively interesting, in addition to being high quality. I would have never imagined my mod would end up there.