It may be that the prism is functional, not for viewing, but for space for some of the necessary components of the system.
People disliking the prism hump on the Olympus OM-D bodies are not aware that the hump houses the 5 axis IBIS.....
So aside from the rangefinder "gestalt" as noted, the retro design may not just be that... retro design. It may be purposeful/functional.
Of course, if they needed the space, they could make the "faux" rangefinder body bigger... perhaps a hump out the back and call it the "hunchback", or one end longer.
Personally, I like the SLR look and it certainly seems to be attractive to old (me) SLR users, and some of the newer crowd.