I haven't decided if I want to start a thread on this or whatever, since I'm not really sure what the thread would say.
I suggest starting the thread, and clearly stating the situation in the first post. Then we can brainstorm some ideas, and see whether there are enough people to actually make them true.
Regarding the two main issues you mentioned:
1. Favourites. I think there's no need to choose one person. If there are several people who'd like to contribute, it's an asset rather than a problem. You could either revolve the host (as mentioned above), or you could split the podcast into sections ("DF Development", "DF newbie help", "DF history", "Podcast DF succession game", etc.) and give each person their own section.
2. Time requirement. I think it would be best to have you in a position where you can contribute when you like, but don't have to when you don't (or when other things, like coding, have higher priority). Having different sections in the podcast helps here as well since it will be your decision whether a given podcast will have a "DF development" section and if yes, how big it will be. Having other sections as well also takes the pressure away from you to contribute a lot to every single podcast.