The EV3 Brick is noted as having digital I/O. How does this differ with the NXT Brick and the interface with NXT/EV3 sensors, motors and Mindsensor brand sensors?

I know the EV3 brick can use NXT sensors and motors, but I cannot find info on the difference communication protocol. Were the NXT sensors and motors analog? Thanks, John

The EV3 Brick is noted as having both analog and a higher speed digital I/O with auto ID up to 460.8 Kbit/s (UART), and 4 motor port with encoders.

The NXT Brick has 4 sensor ports both Analog and Digital: 9600 bit/s (IIC), and 3 motor ports with encoders.

I know the EV3 brick can use NXT sensors and motors, but I cannot find info on the difference in the communication protocol. Are the NXT sensors and motors less precise then the EV3 sensors and motors? Will the EV3 Brick support more sophisticated sensors and motors in the future? Thanks, John