As fun as this is (and I mean that seriously, not sarcastically), my original question can be boiled down to this: today, should 8/8 be parsed as August 8, 2007, or as August 1, 2008? Right now, it does the latter.
I favor the behavior (behaviour?) found in OmniOutliner, in which the two are taken as month and day. Naturally, there has to be an algorithm to guess the year. Given the nature of the tasks here, it should probably always look forward (that is, the date would be the one within the next 365 days). I am sure there's room for argument, however.
I would also agree that the program should look at localization and treat 9/7 as Sept. 7 in the US, and July 9 in Europe.
Of course, we could all begin advocating for <a href="http://en.wikipedia.org/wiki/Calendar_reform">calendar reform...</a>