I definitely understand wanting to remove the router from the network configuration. This CAN in fact be done, however, does require that a technician visits the home to configure the touchscreen to connect to an Xfinity Supplied Wireless Gateway.
If your current modem has wireless capability, give technical support a call at 800-266-2278 and request a technican be scheduled to remove the router. If you do not currently have a wireless modem supplied directly from Xfinity, the only options are to keep the current setup or get one of these modems prior to a technician being scheduled.