Why replacing an E-2 means replacing more than its radar

Could an unmanned aircraft replace the E-2?

Replacing the radar platform is easier than replacing the forward command-and-control role, although those functions could be split across aircraft.

Airborne early warning and forward command-and-control impose different replacement requirements. The E-2 takes control functions forward so that the carrier need not reveal its own position. A proposed division of labour would keep people in a command aircraft while unmanned platforms carried the radar. That would still require aircraft large enough to power and support the sensors. Separating the functions therefore leaves both command integration and electrical demand to solve.