What about this for an idea, just throwing it out there...
Since these Let's Play videos are so popular nowadays, you only really get a single persons commentary on what is going on, and very often its for the first time.
How about a panel of people who know the game, experienced players, and they comment on a lets play video, highlighting areas that could have gone better and discussing the options available to the player. I suppose its a sort of 'coaching' session, but where you get a real insight into the decision process of the play.
Not sure how you assemble it logistically, but you'd capture the video of the person playing, and also the audio of the panel discussing whats going on. I suppose you do the Lets play video in advance, then the panel can watch it, assemble ideas thoughts and comments, and then you do some nifty editing and timing, and interlace the commentary - pausing the lets play - even slotting in visual facts or help at times of discussion. The captured audio panel could be recorded in real time, as a normal radio show, but it would be the clever interleaving with the video that would add a lot of worth to the show - and it would be a new dimension to the RR podcast
Just an idea. Not sure how feasible or how much work it would involve. But I can imagine the benefit of having a number of opinions on decisions made during play, as it plays out in front of the audience.
Otherwise a tiered discussion by the panel, for beginners, then intermediate players, along with anecdotal stuff by players would be quite appealing.