Re: the unsubscribe thing:
What were you planning to use to actually distribute the newsletter? I've been looking at
http://www.mailchimp.com/, which is rather easy to use, free, depending on your list size (dunno how big the active list here is, but if it's less than 501, it's free, anyhow), and has a high level of redundant opt-in/out stuff to avoid being classified as spam.
As far as content goes, I think that the "popular topics" idea is especially good. I liek the "reader questions" idea too, as it can promote a bit of discussion without having to feel like your'e necroposting, or have no real topic on your mind (
Talk amongst yourselves! I'll give you a topic!). :P
Personally, I don't know if I'd be that interestred in fiction. Maybe very short fiction (like 500 words or so), and that might be pushing it. The interview idea sounds like a good one too; there could be "Editor's Choice" interviews, people that the mods/newsletter staff feel are valuable to this community and should be spotlighted, and "Dragon's Choice" interviews, with folks that the community at large chooses to be interviewed.
Going further from there, every X issues or so, you could ask some or all of the interviewees a question, and use their responses as content. I dunno. Just throwing out ideas at this point.

I don't know what I'd be able to contribute to it, if anything, but I'd be excited to see it when it comes out.