Boy there's a lot of philosophy
I am usually about 10 scripts ahead of the podcasts you're hearing, in terms of what I'm writing. (At least, that's the plan...) So at the moment I am writing about philosophy in the Islamic world in the 18th-20th centuries. As you might imagine there is quite a lot of it, and "no gaps" is not really on the cards. But I hope I will be able to give at least a representative survey of some interesting trends. I've been particularly fascinated by something that happened in the late Ottoman empire, where two movements, the Young Ottomans and Young Turks, were inspired by European philosophy to pursue a political agenda of secularization which help gave rise to the ideology of the new Turkish state. That is in the most recent script I've written; now I'm just starting to work on women philosophers in Islam and have been reading books by the fascinating Fatima Mernissi (who I believe will be the first thinker I cover in the podcast who is still alive!).
At the same time I am laying down plans for the next big chunk of podcasts which is philosophy in medieval Christendom, starting with the Latin world and then moving on to Byzantium. I think Latin medieval will take me at least 60 episodes, there is a nearly endless supply of fascinating figures, movements and topics to cover. I could probably do 150 episodes on it, to be honest, but I will try to restrain myself (for one thing it needs to fit into a book). I've been greatly helped already by some experts in the field who have offered generous comments on my list of prospective episodes.
Actually if you look through the existing episodes you'll see that many of them have a note of thanks to other scholars who have given advice or read draft scripts. I have been really impressed at the readiness of other academics to give up their time to help me out - it is great to see that academics, generally speaking, just love their subject and want to help people learn about it and thus help me to get things right!