[TheAntonHein]

For an @Waiting I would like to bring it forward at some time; otherwise I have to do the "thinking". Maybe I should forget about the Waiting context and just use start date to have the @Waiting reappear on the list.

In theory when "waiting for" someone else will do something so you go "ah yes!" but often that doesn't happen. The more you GTD, the more you're following up with others asking "I asked ABC -- what's the ETA?"

I like how you explain the idea of visible On Hold projects.