It would sound more logical to me to buy a stack of pre-made patterns (e.g. coin or cube form-factor) and glue them into a like-shaped slot in a 3d-printed playing piece. Assuming that is possible, and you'd still have to make a conductive path to the person touching the piece, but this would be much easier than printing the pattern yourself.
Sure, a modular system would work as you suggest.
It is not a requirement to provide a conductive path to the person though. The patterns (glyphs as we call them) are detected and tracked regardless of whether they are being touched. However, when there is a conductive path to the person, the system detects that which provides another input vector.
This screams for compatibility with 3d printers. eg: design a piece to be "absorbed" by a LEGO brick (2x4, duh!), and design a capacitive pathway for "two buttons" a-la: https://a.co/d/f7wm3GA
3D print your goblin army, snap it to the base, touch the sword arm to attack, the shield arm to defend, etc. light up the base via capacitive to 0/1/2 inputs and you're set!