I found the cause for the sound issue. Client versions before v97 attempt to map the entire game files into memory for faster access. Depending on how much other stuff is loaded, this will quickly cause the game to run out of virtual memory space. In case of Wine, there are a lot of Linux libs loaded into the process as well, causing it to have less space than on Windows. Pulseaudio then fails to allocate some regions it needs. On Windows this can also lead to issues in environments that require big sprites to be held in memory, such as boss fights.
On v8x this problem isn't directly visible, because there it outright fails to map some of the files into memory (since v8x is considerably larger than v6x).
There are two possible solutions for this problem:
a) Patch NameSpace.dll to never map any WZ package.
b) Set the "large address space aware" PE flag on the client binary, which will allow the process to use the full 4 GB address space instead of only 2 GB.
I'm not a fan of a) because I dislike tampering with original files.
Option b) theoretically shouldn't cause any trouble, because afaik Nexon doesn't do any high-pointer-bit-magic. They enabled that flag themselves in Big Bang. I've provided v62 and v68 clients in the first post that have this flag set. I haven't decided yet whether it makes sense to provide them for higher versions as well. It'll cause the client to greedily gulp up the space with its 1.9 GB of WZ files. It probably does make sense, though...
