As a bit of a follow-up, I think that livestreams of FREDding and modding would be pretty unexciting. Lots of boring stretches, testing, bugfixing etc. And if the streamer was charismatic enough/interestined enough in chat to make it interesting, that probably takes enough focus away from the work of modding/FREDding that I'm not sure it'd be worth it.
Tuts might be a little different, I could imagine a slightly more slickly produced tutorial for some of the trickier elements, or even a series of tuts designed to get you through the basic steps of modding/FREDding with freeware software (Blender -> Lithunwrap -> GIMP -> PCS2), but it'd need somewhere who uses that software to make it.
Livestreams/blind playthroughs of new campaigns may be better, especially if done well (Firesteel's recent Derelict Livestream is a good example, the SpaceGameJunkies guys do something very much like this quite well too).
Reviews, interviews, newsletters etc. Would all be welcome.
One thing that would be cool would be a combination Let's Play and Interview. It'd be fun to stream a LP while the campaign creator was on the stream, so you could bounce players impressions back against the creator's intentions, kind of like a director's commentary on a movie. I think it'd be super cool for someone to play through, say, the first dozen missions of BtA with Mjn chatting to the streamer, or the whole of Vassago's Dirge with Axem. I'd definitely watch that sort of video.