[dm3]

This is a bit different. You are talking about a domain where the developer is usually the domain expert. You know very well what "procedurally generated terrain", "3D renderer", "database", "screen" and "framebuffer" are. Even if you don't - good and unambiguous definitions are usually just a couple internet searches away.

Now imagine you need to encode behaviours for a system where domain experts use terms and jargon you've never heard before. Even worse, users of the same system coming from different departments use the same terms to mean different things. How do you draw the boundaries there? That's what the GP finds disappointing - there is no single guide or reliable process to jump into a new domain and get the boundaries right.