It think it might make a bit more sense (although both are plausible, really) to have the ACW more easily avoidable for Reed and Long than for the Republicans or Democrats, in such a way that the USA can either survive through breaking the two-party system entirely, or a civil war.
I do think the ACW, as one of the most important series of events, should be virtually certain if the AI is in charge, but I think it makes more sense for it to be avoidable for radical parties than for the moderates, seeing as the entire point of the ACW is that the Democrats and Republicans have a very hard time dealing with the social issues at hand.
Ultimately though, it doesn't matter much, and it's up to the modders to decide if they implement either option.
One of the things that should be worked on is Japan, I think. I was pleasantly surprised at the new events for Russia in the latest version, but I don't see much having changed with Japan, unless I missed something major. The biggest issue I see is that there's an event that's supposed to get Sanzo Nosaka into office, but he and most of his cabinet never, ever appear for me. And generally, it just doesn't have that many events. It starts off a lot like Russia, but in the end, your only real choices for where to take the country is a nationalist dictatorship, or a more democratic system that's never really reflected through events, and doesn't have a really big impact on anything.
I admit I didn't play much as Japan in this version, since I pretty much stopped when I noticed no changes after a while, but I would like to know what's new with them and whether anything is being worked on for them.