SoRCon 11 23-25 Feb 2018 Basildon UK http://www.sorcon.co.uk
From Reiner Knizia, with permission to quote:
The optional version to include the random tiles in the caves are not just a cheap add-on. They are a feature which we highly recommend for experienced players. Future expansions will also build on this concept.
(The wording is because I asked essentially were they a publisher add-on, or part of the main design, though I didn't say cheap.)