Why change the servo_switch module to go via commands? It was meant to set a servo directly for ease of setup (without the need to define a command).
I don't see how going via commands is beneficial here, even if you change the command from somewhere else (e.g. radio_control), it would still be overwritten in the servo_switch_periodic.
Maybe make a separate command_switch module? Or does setting servos directly not work anymore now?