Well, right off the top of my head, @Coop_Blimppenny; I don't think any area of the Aetherlight world has lost its potential for new quests!! You guys seemed to have covered plenty of ideas for the Snowmoors and Evergreen Meadows. But for me, personally, I'd love to see more missions that take our characters back to No Man's Landing and more specifically, Engine Bay.
I've found that area to be really interesting, and I think some more action in it would be cool. Maybe something to do with that broken outhouse (which was definitely Lukas's fault, by the way)? But I think it's a beautiful area that definitely deserves more attention in the future. Something needs to be done about those mines haha, or in other words, I want to explode one.
And I hope I'm not the only one. But anyways, yeah. I think that a new mission taking us back to Engine Bay, either to retrieve something like scraps or to fix the outhouse or some other quest; it'd be pretty cool to see and play.
For good measure' sake though, I'll have to agree with @Sierepica_Fuzzywalker and say that @Iliara_Mustardtop's quest is long overdue.