Wine is a compatibility layer for Windows applications. It must emulate all of Windows' bugs and undefined behavior to the best possible extent, even containing a whole bunch of case statements to change its behavior when different versions of Windows are set via winecfg (not unlike Windows' own compatibility mode, which tends to just have every version of every DLL ever in WinSxS to solve the problem...).
To Wine, Windows bugs are features, and applications depend on them. Maybe it will never be perfect, but Wine's philosophy is basically "If it works in Windows, it should work in Wine" -- even if that comes down to an application running in Windows 95 but not later versions, Wine will try its best to keep that Windows 95 app running, even if you have to set the Windows version to 95 via winecfg. If the app doesn't run, it is a Wine bug.