As a matter of ergonomics, aperture rings no longer exist on most lenses for good reason.
And yet, on the brand new 12-50 lens Olympus made the decision to add not one, but two buttons to the place where the aperture ring used to be. Almost as if Olympus doesn't agree with you on the ergonomics issue.
There's a bit of a difference between putting
buttons on a particular lens, versus putting aperture rings on
all of there lenses. You definitely don't see those buttons across their entire lens system.
I think you are stretching here. You say they talk off the aperture ring for a good reason. What do you think that reason is? Is that reason specific to a ring, or does it apply to buttons as well? If so, why did they choose to break it for their latest and greatest lens? If people like it on the 12-50, don't you think they might start putting it on more lenses?
And finally, if having controls on the lens is such a bad idea, why does the m4/3 standard support it?
It's not unusual for lenses to have additional function controls, like AF/MF, IS On/Off, IS Mode, AF On/Off. It just depends on if there's room for it on the lens. Just look at the Canon 500/4L IS, for example. There are tons of buttons and switches on it (below). But that doesn't mean there's also an aperture ring. So, yes, in the case of Canon lenses (and Nikon lenses, and a lot of other lenses), it is "specific to a ring [specifically an
aperture ring ], or does it apply to buttons as well." And likewise, it probably applies to Oly's lenses, too. Indeed, no one is looking at Canon or Nikon lenses and saying, "if having controls on the lens is such a bad idea, why do Canon and Nikon lenses support it?" Clearly, these lenses have controls on them, but they don't have aperture rings on them.
The use of aperture rings on lenses have fallen out of favor in modern times, for various reasons. And just because some lenses support certain controls does not indicate that aperture rings are coming back. Don't think: "Ah-ah! A control button! That means we're getting aperture control rings next!"
Plus, to add insult to injury, I pointed out in a previous posting that the Mamiya/Phase One medium format system has lenses that do have a narrow ring that looks like it could be used as an aperture ring, but instead they've used it as an AF/MF switch! Sorry!
Also, if you look at the Pentax medium format system's latest AF lenses, you'll see knurling where an aperture ring could or should be, but alas there is no aperture ring! Sorry again!
I guess modern camera and lens designers have all mostly decided that aperture control works really well when it's located on the camera, and so they've decided to stick with that. Heck, even a conservative company like Leica decided that their S2 system lenses shouldn't have aperture rings. Sorry for a third time!