Manual flying of the occasional approach or departure, weather and workload permitting is not a bad idea and there are many studies highlighting the need to preserve "basic flying skills", being prepared, and able to reduce the level of automation in non-normal situations is taken a read these days. On the other hand, hand flying jet transports above 10,000 simply increases the workload of the PM, reduces capacity and reduces the safety margin. If you feel you need to do this, get a horse and live in the wild west.