Ability to set and use local (aka the rest of the world), date/time formats. Even if ISO 8601 was available it'd make life for all users outside of the USA and Canada super happy, given just how prominent the Date Created and Date Updated fields are in content; YY-MM-DD over MM-DD-YY please.
Ability to set default sort options in the all Content page - defaults to Relevance, which sort of isn't relevant if the page is being viewed without and search params. Ability to set default to likes of date updated etc., super useful. Again referring above re date time, having ISO 8601 would make it clear to our users what they are looking at.
