I agree - this is driving me nuts! Trying to check critical focus in LiveView used to be easy, using the right hand only, by feel.
Have you had any luck remapping them?
Now, there are 2 methods to zoom - click the play button buried in the bottom left of the back, twice to get 10X during live view, BUT when reviewing images, clicking the same button does not zoom in - have to remember to scroll the thumbwheel.
It's bad enough that they moved the zoom in/out, but worse to have 2, and different, ways to zoom.
Maybe they'll allow programming the buttons back via firmware (yes, the holy grail of fixing UI issues thru firmware).