Creative Assembly have posted a short FAQ on Total War: Three Kingdoms. While most of the questions were answered in the announcement, or it's simply too early to tell (such as Minimum Specs or Mac/Linux versions), there are a couple of important ones:
How big is the map?
"As an Era-scale Total War game, the next flagship game in our series, it will have a jaw-dropping, epic Campaign Map to fit. We’ll be giving you an incredibly detailed sandbox of Three Kingdoms-period China to explore and conquer. Lots more to be revealed as we get closer to launch."
Will there be modding support from release?
"As with previous Total War games, the aim is to have modding using the Assembly Kit, and Steam Workshop support available very shortly after launch."
Total War Saga: Thrones of Britannia will be the next historical Total War game released in Spring, but that's just a spin-off from the main series - Three Kingdoms will be the full, proper Total War, the follow-up to Rome II, and it will be out Fall/Autumn 2018.
Revealing earlier than anticipated, Creative Assembly have announced the next historical game in the Total War series - Total War: Three Kingdoms, the long-awaited and long-expected visit of the series to the China.
"It is 190CE and China is in turmoil. The Han Dynasty crumbles before the child-emperor, who is a mere puppet for the tyrant Dong Zhuo. The brutal and oppressive regime’s power grows as the empire slips further into anarchy. Yet hope blossoms in the form of three heroes, sworn to brotherhood in the face of calamity. Warlords of great families follow suit, forming a fragile coalition in a bid to challenge Dong Zhuo’s remorseless rule. The future of China will be shaped by their hands, but personal ambition threatens their already crumbling alliance.
Inspired by the beauty and artistic style of the age, Total War™: Three Kingdoms breathes life into the heroes of this fascinating period as they struggle to unite China under a single banner."