This is something that could be nice to have in particular use-cases, though I'm not sure if it is worth the overhead. Most of the time users expect issue category lists to be sorted alphabetically, I think.
In case this turns out to be a wanted feature I'd suggest to also add some quick-link of some sort for convenience to restore the items into an alphabetically sorted order.
--------------------------------------------------------------------------------
I think that a sorting command doesn't make much sense. However for sure it makes sense to keep the alphabetical order during the migration. I've updated the patch accordingly.
--------------------------------------------------------------------------------
+1 for the feature, it would be super conveniant when you want to priorize the work by theme within the same priority level.
Thank you!
--------------------------------------------------------------------------------