I have been wondering why this is not an option.
While WAV is certainly nice, why ONLY WAV? I know that FLAC and WAV virtually have the same quality and lossless effect but still, variety would be appreciated to avoid conversions.
Additional format importers is certainly on the list as something we’d eventually like to make available, however, since there are many external tools to allow converting between formats it is unfortunately not as a high priority compared to other features at the moment.
Had the feeling it would be the answer. 
What happened with this ? : (
well i am not seeing it like this, i would more see it like, if you can import any given image format to compressed, then why not for sound, as OGG is very good quality and is nicely compressed , while images are recompressed anyway to DXT, you could do the same with audio for storage purpose only to start