Well, there is one set of skills I think I need some practise with, and that's cutscenes. So I was thinking mission 12 of campaign 3, which seems to be one of those "Much to watch but not much to do but move the story along" kinds of mission, and as such would be a good opportunity to acquaint myself further with the cutscene sexps.
But the main thing of it is that I'm tired of working on stuff that'll likely never see the light of day*, but on the other hand I have a craving for campaign-making that just isn't sated by releasing the odd multiplayer mission here and there. That doesn't mean I can't help test though. As you suggest, any chance to complain is worth taking

*(or in one case, just won't see the light of day until you guys finish up BtRL and release already so I can finally have a container, a ship to move the container and a ship with a landing bay to work with... I even went as far as making a container myself but my truespace skills proved insufficient for the ships

)