I believe the "dangerous beings" reference is just to cover up the delay incurred when an instanced zone like Anguish is constructed.
The "mysterious forces" is more of a conundrum. I have a feeling that they automated the process of constructing paths from one spot to another in a zone and certain paths would be too complicated for the automated process to figure out. It's interesting because they have constructed complicated paths in zones like PoK. I think they prioritized very important "targets" like spell vendors in PoK, and didn't bother to construct paths for less frequently requested targets.
All guesswork, of course.