My thoughts about the new Fengtian-Japan interactions.
As the title says, I'd like to share my 2 cents on the new system introduced in the 1.6 update. I'd like the post to be both a suggestion and a place for discussion, as it may turn out that I'm in a minority - but we'll see.
Generally, I think the old FNG-JAP system was better. Sure, now we have new decisions, events and whatnot, but I believe it has negatively impacted gameplay, and doesn't always make that much sense in-universe either.
From the Chinese perspective, it requires handling Fengtian with extreme caution, like a fragile object. Before 1.6, Fengtian would call on Japan only when in crisis. Now, Japan will join the war as soon as Fengtian starts losing any ground, no matter how much of it they held originally. This means that if Fengtian annexes most of the Qing Government, and then gets pushed, Japan can join in to "save" them when Fengtian's enemy isn't even close to Beijing, let alone Shenyang.
The way Japan coups Zhang Zuolin is questionable, too. Before the rework, there was a power struggle following Zhang's death, one his son could come out on top of. Now, Yang Yuting just takes power, succesfully purges Zhang Xueliang and the entire Zhang Clique, and everyone just falls in line, save for 2 or 3 generals that defect - all in all, inconsequential.
Another matter is the collapse of the Fengtian-Japanese alliance. It used to be possible after Fengtian's capture of Beijing. Now, for it to happen, Fengtian effectively must be ceded a huge chunk of China, all for a, from my experience, pretty low chance of them even making the demand of Japan.
Last but not least, Japan is also very railroaded by that change. When Zhang's time runs out, Japan cannot refuse to join Fengtian's war. Why does it matter? In one word, puppeting. Another one of the 1.6 changes was that Japan cannot puppet allied Fengtian anymore, it must conquer it first. Since Fengtian gets a unique focus tree when puppeted by Japan, and Japan's faction manifesto requires China to be a puppet, it's a shame that getting that result is convoluted - Japan has to end up at war with Fengtian, which requires Fengtian to conquer Beijing and Nanjing/Guangzhou/Wuhan, and then be brave enough to demand concessions from Japan. This has never happened in my Japan runs, Fengtian would always either fail the race against time or join the Sphere with no demands. Getting the desired result demands a lot of gameruling, and even that cannot really guarantee it.
So, on to the suggestion part. Frankly, I would be satisfied with just reverting the entire change, but that's not going to happen, so I have two of them:
Make Zhang Xueliang a factor again. Upon Zhang Zuolin's assassination, have his son attempt to seize leadership of the Fengtian clique. If he loses, we get Yang as usual. If he wins, Fengtian goes to war with Japan and the Zhang part of the tree unlocks. The decision could be affected/decided by Japanese influence, as it was before 1.6.
Perhaps a bit more actionable - at least give Japan the option to not join Fengtian's war. Obviously, the AI would never take it, but the player could, to address the problem I mentioned in my paragraph on Japan.
I think that's all I had to say. I'd be happy to see what the community thinks, and I hope the China devs consider my words.