Other: Worldbuilding guidelines. Specifically demographics - and let's go a little further than 3e did. The default demographics were nice, but I'd like to see some discussion on how altering demographics should change the world. Discuss what happens when clerics are very rare, or very common, for example. Discuss communication and travel times (both for PCs and for things like armies). Help GMs make worlds that play out in a consistent, reasonable manner.