I'm marking this as moreinfo since the patch as is doesn't seem to
satisfy people. Personally I think the key point is that
e.g. date:2012-12-10 should do something reasonable (presumably return
all messages on that day, pax questions about timezone); whether we need
new prefixes I'm less convinced.  However, as far as I understand it,
any solution to the "single date" problem would make the "syntactic
sugar prefixes" rather easy.

As a meta-point, I don't think we should spend too much time and effort
debating TODO; it isn't like this is some contract about deliverables,
or even a document that most of us look at much.