Sorry for the (very) late reply. We have on our backlog a story regarding support for drag and drop sorting of entries (products/variants/etc) in the main listing. I've updated that story to consider sorting of categories as well.
Thanks for the feedback.
It should be possible to drag-and-drop categories to SORT them while in the catalog view in Commerce, not just move them around. This would:
1. Make editorial control a lot easier
2. Give the catalogs the same (and expected) behaviour as normal CMS pages
I reported this as a bug (DI-140869), but was told to create a feature request.