@Tgerritsen we have considered doing a China book, but not Taiwan. In the 1986 timeframe, Deng Xiaoping was far more conciliatory towards the West. We would have had them fighting border wars with the Vietnamese and Indians, and inserted a fictional fight over the handback of Hong Kong (mostly to expand the British to include home guard units and less prevalent vehicles). It would also allow players to fight the Sino-Soviet border wars if they wished.
Even if China was serious about Taiwan and extracted promises of being hands-off from the US, they simply lacked the naval capability to project power onto the island. They wouldn't have gotten any further than Kinmen.
I'd love to see Battlefront make the books official as well, but apart from tacit approval I don't think they'd actually go there. I've written the scenario to be as 'lore compatible' as possible so that they neatly slot into what would become a true WWIII, but I know that not everyone needs that level of 'canon compatibility'.
They get their money from miniatures not rules, and the JSDF were a hotbed of unique designs. They only really have the AH-1 and OH-6 helos available straight out of the gate. Of course, the Soviet Naval Infantry is well catered to, just needing a new Helo (Ka-29TB), new fast air (Yak-38), and a couple of new tanks (T-55AMV, OT-54). They already have the PT-76B from FOAN days.
Korea might be more doable as they're probably 80% of the way there already with the Nam infantry, helicopters and guns, along with using the AIFV model with some M113 turret sprues for K200 and K263. K-55 is a conversion kit for the M109, but only if players really want to count rivets. They'd only really need a handful of new minis to expand their range.
North Korea has a lot of Soviet commonality with T-55, BTR-60 and even stuff like the RM-70. There are some gentle conversions or older models like the PT-76B, the Cheonma-Ho series etc. And then they would be able to further expand Soviet units for Polish, Romanian etc with things like Mi-2, Mi-4 etc.
I play in 6mm so there's already a pretty good service for most parts. I'm having a little trouble with a couple of models like the Type-75 SPH and the KM900 series, but between GHQ and H&R (and a little Scotia Grendel on the side), 95% of the mini requirements are covered.