I guess the company who's cards suffer performance due to Gameworks knows nothing but a random poster on a messageboard knows how driver programming works.
If it was a non-issue like you say then AMD would be better served by keeping quite instead of spreading the news that their cards perform badly due to Gameworks. If you were not good at something it would not make sense to keep bringing the issue up on news sites, interviews, etc.
The fact is that AMD obviously knows that the closed source code is the main reason why they can't optimise their drivers like the could if they had access to how Gameworks code works at a hardware level.
Since Stream processors are architecturally different to the Nvidia CUDA cores the method of performing Gameworks processing will be different.
The simply fact is if AMD are incapable of optimize DX draw calls of a close source project then they have absolutely no right to be in this business and they should do the morally correct thing and hand over the reigns to company with more brains cells than monkeys with downs syndrome.
It is the most ridiculous statement ever, I know it emanated from AMD themselves but it is utter FUD. AMD and Nvidia are constantly optimizing games without access to the source code. Pretty much every game that ships NVidia and AMD optimize the driver for the draw calls without ever setting eyes on the source code, ever. There is absolutely no reason to. The only thing AMD and Nvidia care about is the draw calls that comes form the game,they don't give 2 hoots what code was used to generate the draw calls, only that the game is asking the GPU to compute the given draw calls. AMD and Nvidia's jobs are too optimize those draw calls for the specific hardware.