Some thoughts:
- *seconding the in-depth Hoid podcast*
- magic (rules as stated by brandon (a la essays), examples from canon, speculated unifying theories (foci/intents/fuel/etc.))
- the seventeenth shard (aims, sightings, members known and suspected, possible aims/objectives)
- maybe an episode on unpublished/non-canon works (setting, plot, chronology, possible Cosmeric insights). there are a handful of Sharders who have experience with these, and it'd be great to leverage & share that knowledge (also it'd go a long way to dissolving a persistent "in-crowd" vibe). even though they can't be used for official theorycraft, it'd be great to have a better handle on these books so that, when they come up on the forums/podcast, everyone's on the same page.
I'd love to see topics that were covered in the first two casts (what it means to be a Shardweilder, which books fall in the chronology of the Cosmere and why that's important, etc.) covered in more depth. I feel like the podcasts are a great vehicle for delving into one narrow topic very deeply . I know these first few are introductory, so a general-shallow coverage makes sense. But I hope they get deep quickly.
Also, the podcast could be a great vehicle for live debates - rather than chronicling what we already know (which is a very finite list of discussion topics), have two people (maybe two guests, maybe two regulars who research preassigned positions before the start of the cast) debate and defend possibilities for things that are uncertain (which is a much bigger list).
This would give the dual benefits of providing more than one flavor of podcast (broad chronicling vs. narrow delving vs. lively debate) to keep things fresh & interesting, and giving you more material (thus ensuring the longevity of the project).
Another thought: start each with a little bit more news: not only new releases, but Brandon's tour schedule for instance. I know the info cold be gotten elsewhere, but it would help to make the cast a one-stop-shop for all things Sanderson.
Just my 2 cents
EDIT: my mobile device doesn't like this page's editor