1) Hmm - I'm not sure how this would work but an interesting idea. I'll have a think about how to do this.
2) On my roadmap. See my comment below for more detail.
3) This is also on my roadmap! I'm going to run themed weeks where I get people to create lists on a specific topic (e.g. scifi) and then after the week aggregate all the lists on a special sci-fi page. Hopefully in time this will build a really good topic/genre resource while still having some editorial control to weed out poor lists.
Thanks a lot for your thoughts :)