This is a really interesting example argument because it feels very framed as a case. Suspect, evidence, conclusion. In a more complex case like this, you need more information to cover your bases and deduct alternative explanations. But I feel like a few word changes and a few more premises addressing the assumptions could make this a very strong argument.

So if an argument requires many unreasonable assumptions, that means there are many stipulations needed in order for the argument to be true eg. more hoops to jump through. But if the argument either outlines all of the assumptions as premises OR does not need many assumptions to be addressed, then it makes the argument stronger.

Very interesting... I didn't think about it from this lens: the less reasonable/more debatable an assumption is, the more contingent the argument is on that assumption. Thanks!