If it's RPG-setting-specific and meets the other site guidelines for questions, they're fine.
A question about the Lovecraftian Mythos would be better off in the Science Fiction & Fantasy SE, but questions about the 4e Points of Light setting are on topic here.
The reason for this is that we can have an RPG in any setting--real-life 1920s New England, Middle-Earth, the world of Tron--and that means it'd be easy to have any question about anything be on topic. So we have to limit it to RPG-only settings, both to keep the site from ballooning like a foam dinosaur in the bathtub and because we aren't the experts equipped to answer most of those questions. (Some non-RPG-setting-specific questions are re-opened on a case-by-case basis, and the topic is, of course, open for discussion on meta. The less likely it is that another SE or forum could answer the question usefully, the more likely we are to take that question under our wing.)
The main problem with your question is not that it's a setting question, but that it's asking for an open-ended, speculative list of original ideas. If any answer could be added to indefinitely, and there's no clear way to tell if an answer is actually helpful, that just creates "noise" on the site.