You're using WINE on a DirectX 9c title.
You're emulating the Windows XP environment when you're doing that- which almost always translates into slower runtimes. In this case, the DX9 layer's still not fully gelled in WINE, let alone optimized.
If you were talking an OpenGL title, while it won't be as fast as a native port of a given game, it will be typically faster than Vista will run the title. If it's a native port, done correctly, it'll run as fast as XP and in many cases, slightly faster.
Don't be blaming drivers for this. Don't be blaming the hardware vendors for this. Don't be blaming WINE for this. Until they get the DirectX9c layer better done, you're just not going to see good framerates on Call of Duty 4 unless they offer an OpenGL renderer on Windows for you- and it's not the WINE team's fault it doesn't run well for you as they only recently got the support working at all.