Any emulator including wine is going to have issues. Add that to the required overhead and games that require absolutely top end specs aren't going to run well period.
What is needed is a suite of APIs that completes with DirectX but is easier to develop on.
Actually, I get more FPS running WoW on Linux than I had on Windows.. The setback was the crashes, because WoW was originally made for less than 2 gig RAM.. and happened on both Linux AND Windows, was overcame with someone that made a small indy patch that changed the original WoW.exe to use the +LMB of the PC’s full RAM (in my case 16 gig).
The Biggest difference when running a game (or a heave resource app like Photoshop), is the background. Windows has A LOT of stuff running in the background, whereas Linux doesn’t.
The DirectX is still an issue (most replace that with OpenGL, but it is also becoming aged).
It IS possible to run either the Linux replacements D3D OR the DirectX(WIN) (DX9-DX11), but is a real pain to get it working. I actually had it working perfect once (DX11) and was amazed in the difference between Win and Linux... I wish I could remember how I did it (was about a year ago.. and reinstalled/upgraded since then).