Evaluating "How likely is a war between the U.S. and China?" under the proposed criteria:
- The hypothetical must have few possible outcomes. Yes or no answers can reasonably predicted, the distribution of voters in 2016 cannot.
This is a question with an infinite number of answers. Examples: 100%; 0%; 50%; and an infinite number of shades between them. There's also many possible reasons why there might be conflict between the two.
- Any assumptions must be clearly stated. "If ...", "Assuming...", are core.
Well, let's quote something from the question:
In the past, when a country was threatened with losing its international position, this led to a war (e.g Germany fought Russia in WWI and the reverse in WWII).
That sounds like a possible reason for World War I. That doesn't fit my understanding of World War II at all. That could mean that my understanding is flawed. But since this is unsubstantiated, it seems more like an unstated assumption. Worse, the assumption is contestable, meaning that it will draw answers like flies to rotting flesh.
- There must be an existing theory wherein the answer can be couched, whether or not the theory is correct. The asker does not need to know the theory, but the answerer does. If the asker does know the theory, she could ask "According to The Party Decides will Trump actually be the Republican Nominee."
The question might fit this, but this is a horrible criterion for a question. This means that the question's status should be determined by its answers. So when posted, the question will inherently not be in good shape. It's waiting to be saved by an answer. Evaluating questions should be based on the questions, not the answers.
- The answer must rely upon publicly available information. Nothing about decisions in the Oval Office or Kremlin, unless there have been public pronunciations on the topic.
The question may fit this, but again it's evaluating the question based on the answer. Better might be: "Questions should not ask for private or classified information to answer." The example question would fit that.
- There must be comparable past events, preferably several, from which to draw. No questions about "What would happen if the Mahdi returns?" since nothing comparable has ever happened.
I can buy this. Although I would point out that there is an argument that we have no comparable past events since no hot war has ever involved two nuclear powers.
So where does that leave us? Your example question fails two of your criteria clearly. It arguably passes one. If I rewrite another it passes that. Another criterion is clearly flawed. I find the difficulty that you are having writing an exemplary question for your point troublesome. If you can't write a great question, how can we expect new users to do so?
How's the question doing? Well, it's already drawn a non-answer from someone challenging a side issue and violating the answer criteria. But it's unflagged. That's not a good sign for your proposal for aggressive policing of answers.
Both answers have drawn significant comments which can be problematic. This isn't a discussion site. If people start discussing, the format breaks down. That's the essence of the "opinion-based" close reason. That opinions will be expressed in ways that draw counter-opinions and generate discussion.
As stands, my opinion is that this is a question that should be closed before it attracts too many other answers that don't fit the criteria.