I am sure the E aperture has advantages that can't be acheived through a mechanical aperture, otherwise they wouldn't be going that route. I can't see that it can be that much cheaper or easier to make, unless they intend removing the mechanism to operate the mechanical aperture from the next ranges of cameras, which I personally hope is still a long way away, although it will surely hapen eventually.
I like the new wider collar for the foot as it will make rotating the lens easier, but I am not sure about the foot itself and think it's a pity they didn't use the opportunity to make the foot's attachment platform to the collar larger. That could have made the mount so much stiffer. But overall I think they will be great lenses, and which I could swop my 500 for this one.
As for the 16-80, this is quite interesting to me. On the one hand, they seem to be trying to force us to go Df, then they do something like this?