It’s a weird concept but I suppose it could work, it would be nice to get another country in there but like with Russia any country you can reasonably use will just be 90% C&P, which isn’t good for the main nation or subnation.
Like I said, Turkey could work but may be too big still for the US.
The other issue is that the nations with interesting additions tend to also have a lot of variety, something with a small military but unique vehicles, not something I can think of off the top of my head
As a south Korean, emotionally what I want SK for is own tree with NK.
But thinking of gameplay, it would be okay with sub tree of Israel with turkey. SK tree’s strong point is on it’s mbt and big gun light tank, while weak point is SPAAG.
Israel and turkey has good candidate of SPAAG, while Israel lacks good MBT on its top BR(just another Merkava Mk4 based one left)
While Israel and SK has some military bond. SK acquired and examined T-62 and T-72 from Israel as they send captured ones) and quite amount of indigenous developed SK weapons uses Israeli components.
What SK peoples do not want is being sub tree of USA. First, USA tree is already too big so SK being sub tree of USA would mean just some vehicle like current Benelux sub tree.
Second, US team sucks because so many new inexperienced players choose US as first tree.
5 lines is already limiting, it’s only going to be more so in future, also they need to do helicopter tree style split line for China’s first air branch, splitting it into ROCAF and PLAAF light fighters
I mean, some nations could use more lines for domestic tech, but add a few more lines for more “1-line” sub-trees is flawed. As it still limits what could come.
Sub-trees need dedicated tabs. They should look like a full nation but could still be mixed with the host nation.
What if they made it so SK and NK had their own folders, SK linked to US, and NK linked to China/Russia, but if someone wanted to they could put SK and NK together for AB and RB, but for sim they have to either play it with the linked tree or just the individual NK/SK folders
Read the nation folder suggestion, this doesn’t mean you can only play SK with US if using nation folders, my idea at least is that if someone wanted to they could have a united Korea lineup but if they wanted SK stuff in US lineup they could, same as how if someone wanted to add NK stuff to a Russian or Chinese lineup they could