I've been wondering why China was able to unify and not Europe, and came up with some really good ideas. I was going to ask the question then answer it, but I realized that it wouldn't fit the Q&A format of the Stack-exchange. I feel that this sort of question would be a great addition to our site and would bring many people to the history overflow, and was wondering if there was a way we could ask and answer this question. Any ideas?
I think there are plenty of ways to do that as is. Typically this is done by asking a specific question on which elaboration and supporting examples are required "why China was able to unify and not Europe", seems to be very much an example of this. The fact that this question cannot be as definitely answered as say a mathematics proof or a physics experiment is simply due to the more complex nature of history (ie. many unknown and un-isolatable variables and far too extensive of a scope to reduce to a laboratory experiment). If the format doesn't allow this it is not proper to historical analysis.
Have you tried asking this and its has been downvoted or closed?
If you think this question is good for the site and will bring people in, and also think that there are risks to answering it I would impulsively say its not a good question. Personally, when I encounter questions I would like to ask but have a "gut check" that says I should think about it then either my question is ill-formed or ill-suited. When framed correctly historical questions can typically be answered, but usually there is not just one correct answer, in many ways thats where I feel the History SE site sort of diverges. Since SE aims for one question with one correct answer it's hard to say if there is one that is the most correct, mostly I go with the most suitable. Although I have seen many programming questions that don't have one correct answer either, so I don't fully think that History is that much of a divergence.
Sometimes the risk is worth taking, if you have a question that has value and have an answer of equal value then feel free to put it forth. There are a few examples of questions that were either closed, or considered ill-suited to the History SE site but elicited some very good and very high quality answers. So my suggestion to you is don't overthink it, after all this is a community site and unless the community participates it will not grow.