One of the main purposes Adafruit looked into getting a couple of R.O.B. units was to hack on them. With the control protocol unknown and tube TVs long since sent away, we thought we could take over the motor control.
The new Adafruit Crickit control board and the Circuit Playground Express could easily help in giving R.O.B. the smarts to bring him to today's standards. Crickit can provide functionality and CPX has all those sensors.
You could use a Crickit along with the existing motor control chips inside R.O.B. This would leave more control for a couple of motors to motorize the base so R.O.B. could move around a room.
If you wanted control besides the existing optical input, you could pair a Wi-Fi or other radio to send commands to Crickit via a receiver (or even use a phone as the controller).