Unit formations are back, but they're tied to characters Absent in the Warhammer games, unit formations are an extra tactical layer that effectively shift or buff the function of a given unit. For some, it was too much micromanagement, but Three Kingdoms will introduce them more naturally over the course of a campaign, and tie them directly to certain heroes in your retinue.
Mann explains:"With Total War: Three Kingdoms, we're really pushing the concept of characters, and actually certain characters will be bringing these formations in to get them enabled for the rest of your army. So by default your army potentially can't form a diamond formation with its calvary. But by bringing a high-level strategist in with you, they're actually able to give you those formations, so it's kind of something you progress into as you're playing through the game."