Custom order categories in admin dashboard

Use the get_terms_args hook and modify the orderby argument, like so:

add_filter( 'get_terms_args', 'my_sort_terms', 10, 2 );
function my_sort_terms( $args, $taxonomies ) {

    $args['orderby'] = 'description';

    return $args;
}

Possible values for this argument are listed in the codex.