- better DR or higher resolution (i'd vote better DR though in RAW and NOT JPEG
- fast SD slot
- some better ergonomics like assigning autoISO to a button, or even when the SET button when is assigned to adjust the ISO value by holding it and rotate the front dial, in the current condition/firmware it doesn't go to the autoISO, and you have to set it manually each time from the ISO button.
- PLEASE please! assign a button to custom WB, rather than taking an image, set the wb to custom, load the image.. DAMN! one click thats it! RATE and magnify buttons are useless assign one of them at least!
who uses RATE and JPEGs in such a beasty camera anyway..
- Restore magnification buttons in live view like its been in mark II or any other model. (hard to find the magnification button in the night which is in the other side of the camera)
well actually most of my requests can be done with a firmware upgrade
in two words?, more button customization
but an upgraded sensor with higher DR is a must for 5D IV