I'm becoming more and more tired of people saying "It is impossible, it could not happen", and their only explanation is "It could not happen, because it did not happen".
Some people seemingly don't have any imagination.
In the AARs I saw one or two things, that made me wonder whether such an outcome could be possible in RL. But I don't think there is something wrong with Germany victorious in WWI, Mexican colonization, or tech trading.
1. German victory:
Sytass achieved more in then Germans did in RL, but it was not a walk in the park. There were two important factors, that did not occured in reality: Sweden & Italy joining Central Powers.
Especially the latter is important: Germans weren't that far from victory on the western front in RL, and if they could count on Italians help, the outcome would have be obvious.
2. Mexican colonization:
Take a rest. What's wrong with fairly rich country, wisely guided, taking one small colony? The UK would never agree, blah blah. They did accept Belgium colonies, didn't they?
3. Tech trading:
At first, I thougt that maybe there is something wrong with the fast pace whith which one can gain techs by trading. But it is actually the thing that happened in RL. The inventions weren't made independently in diffrent countries, but purchased or just copied from the inventor. And it did happen rather fast. Think about, say, positivism - how long did it take to spread that idea.