Lately I have been wondering whether a "fear" (for want of a better word) of hand-drawn diagrams are causing diagrams in general to be under-used. We're used to having everything typed, TeX:ed, machine drawn, perfect, and we want our diagrams to look like that, too, but using drawing software is hard and time consuming, so we don't diagram at all. But we could just whip out pencil and paper! You don't have to be an artist to draw some boxes and arrows. And the problem of archiving and revision control is solved now that everyone has a digital camera in their pocket (and a JPEG file of an A4/letter page isn't very big by today's standards).
The best planning experiences I've had in a team were when everything was done on a whiteboard and photographed for posterity. Architecture planning, kanban board, UI mockups, everything - it was a joy not having to wrestle opinionated tools into doing what we wanted.
