A true raw histogram would require the implementation of RawDigger onto the camera. So on top of producing the video image for the EVF, and all the other functions like subject detection, eye tracking, etc. the camera will have to run a version of Raw Digger. These processors while powerful are designed for imbedded systems not high performance laptop/desktop computers.
There is also I think an open question of how much more information would a "raw histogram" provide vs. a much easier to compute histogram off the JPEGs. I'm not sure the issue with the utility of the current histograms is not more related to the fact they are derived after all the JPEG processing of the "film simulation" which vs. a robust measurement of the light spectrum.
In Magic Lantern implementation they just do it, no RawDigger there.
BTW RawDigger is a very lightweight application.
Computing histograms from JPEG, by comparison, is a more computationally intensive task.
When I shoot raw, I expect to see the histogram of the data I'm recording into a raw file, not some abstraction through a rendering engine, which, btw, isn't the same I will be using for my raw conversions.
Histogram being distorted by the application of white balance is quite often very misleading and results in photographer using exposure up to 2 stops lower than possible. Histogram that is calculated according to the midpoint and white point calibration for JPEG is misleading when one shoots raw and also directs towards exposure that is lower than possible.
While JPEG brings the midpoint to 18%, in raw it can be 12%, 9%, and even 6%, leaving, to quote Adobe, "a significant amount of highlight headroom during a normal exposure" which "also means normal exposures will contain more shadow noise".
its a great test image. a white bird, direct sun. and everyone thinks you need to shoot raw to preserve white feather detail. not on the a74 and useing Very fine Jpeg.
so you have obviously compared the both files. and see little difference when applying the same adjustments to the jpeg.
it was a great image with shadow covering half the bird. so clean shadow detail was much better with the jpeg , got them every time . they tried and tried for days with one person finally posting an image near identical. but as illah demonstrated he just posted the embedded jpeg ,so it might have been a dishonest conversion anyway as i hadnt even thought of that. back in the days of my Pentax K7 no program could produce the very fine detail the incamera sharpening could produce.
All that image does is provide further proof of my point #2 earlier.
"I have also posted on numerous occasions that with today's modern cameras and with a large enough supply of bananas you can train a monkey to take a nice looking sooc jpeg in good light. The raw file you posted was of a scene in good light."
Point #5 described a better test image but you have never posted one because it will clearly show the benefits of raw over sooc jpeg.
Then, as a writer of real English, it would have been better to write "if you were to practise", assuming that your schooling included English grammar.