So I've really only ever used DATE! once. And that one time I did use it, I had to convert it to an ISO date and timestamp.
A New Option: PATH! for dates
So syntax-wise, there's nothing stopping you from making the PATH!
12/Dec/2012 if you want. (Well...or the tuple
2012.Dec.12, if you felt like it...then you could combine it in a PATH! with something else, maybe a TIME! 2012.Dec.12/0:00...though TIME! is currently illegal in PATH!)
Anyway, PATH!s present a fairly reasonable LOAD-able format for dialects that wanted them...that you wouldn't have to put in quotes. Their TYPE OF wouldn't be DATE!, but you could work with them structurally. Then you could convert them to and from the ISO dates.
I don't know enough of the issues to know exactly what all would be entailed in ISO dates. One theoretical benefit might be being able to use a vetted date library for arithmetic.
Reply here with concrete examples that contrast how DATE! works today and how you might imagine it working in an alternative more-ISO-friendly way.