1) Previous approval for all new threads;
2) An option to delete comments;
3) An option to move threads from one category to another more suitable one;
Regarding the third option, I would like to make a suggestion. It's entirely up to WF to decide where to put a new thread. Yet, while we wait for a minute to be published, it shouldn't be a problem for WF to wait for another five minutes before moving it to the more suitable category.
This five-minute delay shouldn't hurt WF and the author of a new thread is allowed to spend some time in the first category of his choice. Would five minutes make a difference? Probably not, so we should have nothing against it. I think that some interesting ideas and questions are automatically "disqualified" by being moved to "off topic" category. This isn't a big deal, but the possibility to attract additional attention and therefore more opinions is automatically diminished.
Again, this is only a suggestion. You can try it and see how it works.