We know the next total war saga will be upon us, next year.
I am pretty sure it will be a period set in China. If I had to guess, it will be a Warring State era even though I would prefer a Tang Dynasty Civil War.
However, I would like to point out the problems with a character centric total war for a Saga standalone expansion or even a Chapter pack that is out of 3K period.
The thing about Romance of the Three Kingdoms, it is a pop-culture and many fans are used to their stylized attire. So, when some total war & rotk fans sees weird attire like Xu Chu's lightly armored appearance (keep in mind, he is the commander of Cao Cao's elite bodyguards) majority of us could still accept it and also other characters appearance that might not fit the timeline of that period. Since most of the historical tw fans are quite particular about realism and historical "near-accuracy". For me, it doesnt have to be 100% historical accurate, a near-accurate would be fine and less over-the-top. I know am contradicting here but ROTK is the only exception lol.
However, for periods outside of ROTK, things are very different. Eight Princes for instance is a good example, had CA went for a different approach. For example, making the princes wore what a prince should wear during the period (despite being clones but majestically accurate) while putting more efforts on improving on the units would have created better value for the DLC. The over-the-top attire, for example Sima Jiong (wearing leopard skin) and Sima Wei (look like a bandit or thug) doesn't give the impression that they are princes. Even though the models were done meticulously, it does not really add value in my opinion.
I am speculating the DLC is going to perform average if not below average as most of my friends on steam who pre-ordered TW3K months before release, just could not be bothered with Eight Princes (yea, I know it is a small sample but judging from steam's top seller. There's a correlation.)
I do hope the Saga standalone expansion would be a success and not a repeat of Thrones of Britannia.