We are still terrible at digital photography

we should capture 3D (matched image sensor to LIDAR)
we should capture light functions, not accumulation (obviate HDRI)
we should capture better than rec.2020, becaues the world is green, and guess what we keep not capturing
we should capture light fields
we should capture the whole image, not "the optimal-for-film rectangle".

Should be illegal if missing:

USB-C for data as well as (fast) charging
using the camera while it's charging
full camera control over USB: the camera's firmware should have mirror-apps for win/linux/macos/android/ios with the exact same content, using the exact same menus, and sync those by wire or over the air
- Not "suites", fuck that noise: dedicated applications specific to that camera that come with your camera on a USB drive, and are updated in lockstep with firmware updates.
data transfer of any data on the SD card, byte for byte over wire or air (NFC, WiFi, USB)

top LED menus: nice bright touch screens have been a thing for years.
physical shutters: electronic shutters are superior in every way
mirrors: EVT show what the camera sees, and is just a video stream so you can add overlays, processing, etc. (heck, add a dedicated 'show pure' button, similar to ancient DSLR's DOF preview)

ISO values: leveling curve + LUTs
white balance options: curves/LUTs, again
E/V compensation: oh look, curves/LUTs, again
Filter presets: OH LOOK, CURVES/LUTs AGAIN!
all these things are different sides of the same die, and all of these can be zeroes out with built in color calibration: shoot XRite Color Passport or similar device and be done 99% of the time.

video recording length limit: NO ONE CARES about the fact that your camera costs more if you have to pay the video camera tax. Fucking work it in.
custom batteries: USB-C fast charging is universal, battery banks are universal, there isn't even any math to do here: stop wasting money on proprietary batteries.