Harry:
I can hear Ansel laughing from far away Valhalla.
BUT, you are on to something, imagine a mono digital camera that has a similar function to modern exposure mapping, but was pre-set for zones, real zones set by the photographer, or chosen from a group of presets. The thing I hate most about modern photography is that it isn't convenient to go manual. Imagine a camera that was designed to be driven, rather than a glorified point and shoot. The mono should not be criticized for what it is, but rather, what it can/could be.
Well, the roots of this problem lies in the background of many of the engineers, who may have come from the world of video.
I work in movie production and over the past 10 years we have experienced the long march to digital cinema.
In the early days digital cinema cameras were glorified HD video cameras.
Then came a few more specialized attempts like the Thompson Viper etc. Again, mostly based on HD video cameras.
In addition to the lousy dynamic range of these early cameras one of the big problems was the distribution of the available stops above and below mid gray. For some reason video cameras tend to be set up by default with more stops available below mid gray and fewer above. Film works the exact opposite way. Lousy shadow detail, but never-ending highlights.
It really wasn't until recently with the arrival of the latest generation digital cinema camera, where we suddenly saw the distribution of stops flip back around to the way film works, where you have more headroom above gray. This is probably due to the 'video' engineers finally listening to the cinematographers.
We see a similar situation in digital photography, but there still is a long way to go.
In the case of the M9M is makes absolutely no sense if the distribution really is -6/+3. If there is a company on the planet that should know better, it should be Leica.
Permanently setting the exposure compensation to something like -2 stops
for daylight shooting would shift the balance to be more film like. Some experimentation would be needed to discover just how the dynamic range is distributed and find the ideal settings. This does not mean that shadow detail would be totally lost. The M9M appears to have very low noise, so there would be no reason why you could not lift the shadows in the RAW processor and restore detail. If you were shooting at night you would probably want to leave it at the -6/+3 split, so you would have maximum shadow penetration.
The problem isn't that we are lacking in some zone mapping exposure feature. We really need two things.
A sensor that delivers 14 stops of range like film negative.
The engineers need to choose the distribution of the available dynamic range so it doesn't mimic a video camera. With 14 stops a -7/+7 split would be the most flexible.
Once you have that it is up to the photographer. They need to learn the exposure characteristics of the sensor, just like they would a specific film stock. I've shot thousands of rolls of Tri-X and know how it behaves like the back of my hand. It's the same with digital. You need to learn how the sensor operates and set exposure accordingly to get the results you want.
