[cturner]

Regarding pencil and paper, I sense there to be a huge gap in notations used for representing ideas on paper/whiteboard.

Relational schema diagram notation is useful. You pick up some along the way, like "mind maps". UML is very heavy, and I don't know anyone who uses that for flow. So for most things, each person invents their own method of capturing ideas.

I've got a couple of tricks that do work for me. But the notations I use are unsophisticated compared to what could be done if this issue - smart ways to develop ideas - was a meme that lots of people were working on.