Well, we need to start with the basic SE requirements. The question should have a definitive answer that can be chosen. (This is why so many people vote down list questions.)
As I've said elsewhere on meta (This site is doomed and Appealing to Heinlein/Asimov), I find most interesting and valuable the questions that ask about the science behind the science fiction. Either analyzing how a particular thing works in fiction (see Why phaser beams are different colors, Rate of mutations for Waterworld, Human power in the Matrix, or How Star Trek became chashless/commerceless) or how the particular concept described would work in other situations (Would the terraforming techniques from Red/Blue/Green Mars work on other planets).
I also feel that questions about obscure or uncertain facts from SF are worthwhile. (The role of the Tunnels & Cruciform parasites in Hyperion, Is Klingon a fully realized language, Why does the Enterprise dedication class say "Starship Class, and Why do anthologies play such a big role in the history of SF.) (The two questions you mentioned above are of this sort.) The trick here is to have the question avoid the too trivial mark while still remaining interesting.
There is a strong division about recommendation questions and list questions. I like them both, particularly the focused list questions such as Books that deal with the Fermi Paradox and Fiction that relies on P=NP. But we'll have to wait and see the will of the community on them.
In addition, there is a division about whether to allow "help me remember" questions. Again, I like them, but the community has no consensus (beyond the decision from gaming.se, which still appears to be controversial as applied to SF).
Even if these three types of questions are disallowed, there appear to be a number of questions which would be useful.
