> I can't remember any occasions where the diagram actually cleared things up though.

I would be very concerned about the quality of the engineers I was working with if they couldn’t produce helpful diagrams.

It’s not coincidental that discussion of system architecture is usually accompanied by diagrams. They should be helpful. And in fact…

> Coming to think of it, one way that seems to be pretty effective at getting complex designs across is in an interactive presentation with the presenter drawing on a whiteboard, starting simple and adding stuff while explaining what and why.

You seem to agree that they are helpful.

> The whiteboard drawings by themselves are absolutely useless.

This seems like sort of a straw man, though. I don’t think anyone advocates for system diagrams in the absence of any context.