It's a given that mfg. cost of 2 boards is higher than one single board.
May be feasible to fit everything on a single board.
concerns are;
I/O connections. keyboard matrix is already littered everywhere, and we rely on a connector to bridge the signals over. this would constrain everything to the traces of an already broadly (and necessarily) occupied 2-layer board.
It's a given that mfg. cost of 2 boards is higher than one single board.
May be feasible to fit everything on a single board.
concerns are;