All that I'm hoping for in upcoming cameras is to add M* to the supported modes for exposure compensation, where M* = M with auto-ISO enabled.Some cameras, notably including Ricoh GR which I happen to own, have a separate "TAv" mode, which is basically "M with auto ISO and exposure compensation", whereas in regular M mode you can't set ISO to auto at all. A bit strange perhaps, but works. More important though is that it does have enough dials for shutter speed, aperture and exposure compensation, re-purposing a rocker button that's usually used for ISO setting in other modes (which of course also makes changing ISO harder, requiring at least one extra button press).
I guess that the thinking is that if you are in M, then the two dials would most often be used to adjust the shutter speed and the f/stop, so you run out of dials to adjust EC.
Thinking of Canon's ergonomics, I guess EC in M would have to be behind some button-plus-dial combination, or especially if they add a separate TAv mode, either shutter speed or aperture could be done that way and EC directly (ideally customizable any way you like).