These are indeed not really feature requests 🙂
Anyway, I believe the time entry is dependant of your language:
if (preg_match ( “/en|sk|zh|us|uk/”, $locale_code ))
$hours_locale = “12”;
So I’m guessing that your language settings are the culprit here, but I’ll take a look at it (I like 24hr format better as well).
For the date: this is a javascript popup, so I would guess the format is not that important, no?
The format overrides: a bit difficult to put in a sidebar (or a different tab), but maybe they can be collapsed or so …