Hi,
I would suggest that you may overstate this a bit. What Roger Ciala says is that the Sony lens performs better of axis than indicated by MTF. He found that lens to be about the best when using Imatest. The "Sony Zeiss" has the exit pupil more to the front than the other lenses, thus reducing the ray angle.
Thickness is a problem with all digital sensors. There is always an IR-filter in front of the sensor. Often there is also an OLP filter consisting of two Lithium Niobate monocristals and a wave plate. That optical package needs to be taken into account when designing optics. If the OLP filter is eliminated I would expect it to replace with optical glass of equivalent thickness. Leica has similar issues, they have reduced the thickness of the IR filter to an extreme, to counter it. I would not expect it to be a problem with DSLR lenses like the 14-24/2.8 or the Canon T&S lenses.
Regarding the problems with internal reflections in the adapter, I have seen something similar (but worse) when I adopted my Hasselblad lenses to my Sony with an Arax adapter. A much more expensive adapter from Mirex has movable internal baffles reducing reflections. It can be a problem for sure, and it needs to be adressed by adapter makers.
Regarding the third issue, I have not heard about it, but it is generally a problem with digital sensors that they reflect much more light than film. Lenses that are intended to be used with digital cameras usually have better multicoating on the rear elements. Reflections from aperture blades is also possible. I don't think this is a Sony problem, but it would be a problem using old lenses on Sony.
There is also a discussion about the shutter caused vibration problem.
Rogers article is a very good read:
http://www.lensrentals.com/blog/2013/12/a-bit-of-a7r-sanityBest regards
Erik
I think the D800E is still a better choice than the A7R. The Sony A7R has some issues with adapted lenses:
#1 (Non native lenses) lens performance in the corners is greatly reduced due to the glass in front of the sensor that is actually part of it. This was discovered by Roger Cicala of lens rentals.com, you can google the numerous threads online about this. This is an issue with wide angles 12-24mm range it seems. I read somewhere than a new adapter with a corrective glass is necessary to fix the issue. This is developing story so it has not reached a conclusion.
All these are serious issues for critical use in a wide range of conditions.
Of course I think Nikon but specially Canon is loving these issues. The A7R is a great camera and a game changer for sure. Once these issues are resolved it will be even better.