Viewing a video with multiple languages that doesn't happen to default to the correct choice is impossible with Parole. This means I have to use VLC in those cases.
Yes, lack of ability to change audio tracks (whether language dubs, dvd commentary etc) is a big missing feature for me.
Yes, it would be nice to be able to switch between different audio stream in a file.
If there is more than one audio-stream or if there are subtitles available, an infobar will let you choose between them. We're also working on adding those options to the menus.