WordPress desperately needs a core function to set the sort order method for EACH category AND whether or not it is applied to child categories. It could be administered from the category admin page... something akin to Page templates, at the very least... a menu to select the category template for each category would suffice, though an option (global, I guess) to apply to all child cats (or pages) if checked would work... overridden only by a different choice made on the specific child cat or page.
Currently, there are no reliable plugins that cover this, especially to apply the settings automatically (or not) to child categories... custom functions have to be placed in category-specific templates. If you use a lot of categories and sub-categories, you have to manage a lot of template files (eg. category-n.php)
I often just resort to using Pages and setting up queries for posts in specific categories... but this is clunky and defeats the idea of cats versus pages. The preference for Pages IS that I can set a template. All the logic that is core to WordPress can be used in a Page template.