It is possible the problem is AMD-only, but i cannot test it because i dont have AMD cards. AMD is not good for gaming.
AMD is fine for gaming. Some games work better with AMD, some with nVidia, I'm sure you know this. More to the point, AMD cards are not prohibitively expensive for many people.
If you don't want to support AMD then just release a version of OR that works with AMD, like 6.5 o earlier. If you prefer, just release a version without the new shadow code and freeze it there - most people will be perfectly happy with that.
As things stand the only way to get OR working on an AMD card right now is to not only disable shadows but to delete the new shaders folder. This makes 7.0 a downgrade for anyone with an AMD card because they can't use the new shadows OR Enhanced Camera.
I already sent him a shader log. Don't know if he saw it. Don't really see how amd is bad for gaming tho. Depends on the game. My r9 390 is 4 years old and I still play most games on ultra settings. Actually aged better than the 970
Amd gpus generally age better. However it's true that for high end gaming gpus Nvidia is still the best option, performance speaking.
However again, this seems to be strictly a driver issue (or maybe a driver/OS or a driver/DX9 interaction issue),as with a different driver (lib32-mesa) on linux I don't get any transparency issue, in wined3d or Gallium9 backends.
I have a Vega64 and I've been having a similar issue with OR 7.0. I've noticed with OR 7.0 that a variety of objects including eyes, armor, and hair among other things, seem to become invisible or highly transparent under certain conditions like in exterior cells or when there are nearby light sources. I went ahead and renamed the Extrashader folder and sure enough it solved the problem. I also managed to create a shader log.