I should just have quoted only the very first sentence of your post 'Those characters still had their feature episodes, just not as many as Janeway, EMH, and Seven of Nine. ' because that was the one I was really responding to. But I agree with your main point that you don't need feature episode in the first place with a bit of diligent writing. On the other hand, as I argued, with writing that's only interested in getting a one-off episode, you'll get feature episodes that don't develop the character. I think they just wanted to go for a quick 'life is hard in this neighbourhood of the DQ' vibe and didn't think beyond that. But I agree, water should be one of the easiest resources to procure if you are warp capable.