Can there be a shanty mode where you hit buttons on your controller/keyboard in sequence to play the notes? Like RockBand or Guitar Hero? And then if you play a perfect song (or concert with a crew) you get achievements?
Shanties right now are a fun distraction / roleplaying element, but it'd be cool on long passages to have something to practice. And you could have "battle of the bands" with other crews.
Lastly, as you got drunk, there should be a delay so it was harder to hit the notes on time.
That's all, thanks for listening.