On this one you are wrong. Optimization can only occurs in routines without changing specifications (read tim sweeney response). When you can run DX9/Opengl card independant routines faster without changing specs at all, this is optimization.
When you change routines specs, you cheat whatever you notice or not the difference.
Many don't see the difference between 1024 2xAA 8xAF and 1280 4xAA 16xAF, so if ATI or Nvidia decide to replace one by the other saying it is not noticiable is realy bad faith.
As soon as there is some sort of code that detect what software is running in any driver, IT IS CHEAT. and the "bug correction"/"optimization" thing is only an excuse.
If NVIDIA or ATI thinks a game is not programmed correctly for their hardware, they should release an independant patch "UT2003_NV35.EXE" and NETHER do it in drivers.
As a company game i could sue them for copyright violation otherwise.