It is possible to have a female plug and a male socket. Its just careful use of language ignoring the common and incorrect usage that all plugs must be male. If its on the end of a lead, its a plug.
The present "standard" for servos, 3 wires, -ve at one side,+ve in the middle and signal on whats left, arranged in a neat row spaced a 0.1", running on a nominal 5 volts and using pulse length encoding is so common that any RX maker who tries to step outside of it is going to wind up with very few customers.