You know these sorts of bugs are hard to tell if they're a WINE bug or a catalyst bug. Have you filed a bug report at winehq? or searched for a similar bug?
e.g. (Ubuntu 9.04 x86-64 P8600 4GB mobility 4850)
wine 1.1.31 + cat 9.10 GW seems to work perfectly
wine 1.1.32 + cat 9.10 GW char selection screen garbled, flashing triangles all over the game play screen, X3 Reunion all sorts of weird distorted textures(think that this is the GW char sel screen problem) in gameplay, scrambled game menu, etc.
In the above cases I'm at leats partially inclined to blame wine...
Intel Core 2 Duo P8600, 4GB DDR2-800, 320GB 7200RPM WDC WD3200BEKT-22F3T0, ATI Mobility Radeon HD 4850 512MB GDDR3, 8x Super multi DVD+/-RW, 1680x1050 (17"), 9 cell battery
Ubuntu 8.10 x86-64 (current updates) catalyst 9.3
Windows Vista Home Premium 32b SP1 (current update) still on shipped catalyst(8.12 I think, MSI packed -- lazy)