One thing that has struck me is that setting (and here I mean setting in the sense of creating a world in which to play games) is often overlooked as part of the design process.

*Please don't discuss that statement in this thread*

That caveat right there is there for a good reason. I'm not saying that the point isn't debatable in itself, but that's not what I want this thread to be about. No, this thread is laying out a manifesto of sorts, getting started on something that I have been thinking about for a while.