Mandatory RVSM with its potential lowering of the bottom cruising level makes it difficult for pilots to manually handle their aircraft at cruising levels. It ought to be possible for Air Traffic Control to release aircraft from this requirement for a finite period when and where ATC can allow. Not all airspace is always busy throughout the 24 hours. ( A simple example is the Aeropostal night flights from Paris, when and where much of the area is virtually empty. )
Not all flights are from busy areas or at times when they are busy.
( On another thread someone mentioned that their airline arranged that their pilots did two sessions of manual flying as well as a further couple of sessions in the sim doing all the mandatory stuff, annually.)
Some of the " analog" aircraft tended to have higher weather minima ( when these were laid down, I think, in the 1950s). One Captain used to say that he would overshoot when he saw his F/O "BRACE"... But he may have been joking !
In 1975 when most Jet cruising levels were 2000ft apart, in discussion with the UK Authorities, I was told that they were considering reducing this to 1500ft to allow more flights to cruise nearer their own optimum levels.