But those who do no use also will then not be able to run shiretoko. Libasound is the same libs that are in the alsa extension, and being the exact same files it will cause no conflict. When alsa is updated, libasound will be updated with the same files.
But what I have been planning to do anyway was to have a alsa-lib and alsa-utils extension to be more consistent with upstream and to ease maintenance. In that case, alsa-lib will be the dependency for shiretoko and will not conflict with OSS.