If going retro is the same as to (re-)introduce some more straightforward mechanical design for the most important settings, than going retro for me is a good thing that should not be disregarded as if it was a mere fashion.
e.g., I'd be happy if Canon-lenses had an aperture ring again, especially macro-lenses and TS-E lenses. Having the Iso more accessable when wearing gloves would be another great thing. Overall, I really dislike the need to push little neighboring buttoms while turning a wheel.
Just because Nikon messed it up with the Df, Canon should not be to proud of their own rather lame design.
But I must admit there is one great thing about EOS-functionality that I wouldn't want to sacrifice to any designer's needs: It is the positioning of shutter-release, digit-wheel and how one's hand fits into the grip. Allows to adjust most everything manually with one hand, including ISO (although that I would prefer on a designated wheel, like I said, but maybe that is just me). Try setting all that single-handed on a Nikon and you will likely drop your camera in the process.
Conclusion: I wouldn't mind having a few more accessible wheels on top of the camera. The G series has always been ugly, but it worked. A7 isn't exacly pretty either.