WoW client works fine under wine (tad better than under Windows imho).
Really? And what is the major improvement/difference, besides running under wine/in linux?
Swap performance and VM handling, frankly. It's better at not putting things in swap it shouldn't, and quickly getting things off swap it needs. Generally less lumpy if you aren't swimming in memory like I'm not.
I also get the added benefit of instantly switching in and out of the game with virtual desktops, and being able to shut down all unnecessary systems and programs, and SIGSTOP/hibernate large things like firefox so they sink entirely out of memory until I call them back, and I have total scripting and file control over all my addons and logs and things.
Also, crashes won't take out the box, and if things get really gnarly, I log in behind my GUI remotely and shoot things. For some games that are going under due to game corruption, flicking to the CLI, Kill, restart, can get the game back before the server has given up on your connection. WAY faster than Windows.