That's true, and I'd like to see how NCL fares if they can get going 100% vaxxed.
It can't be good to have 25+ crew out for any length of time, though I'm not sure what the answer is there. When off duty, they are - in a way - home. Whether in crew quarters, mess, or letting off steam at the crew bar (the latter being a place of eating/drinking, though public). The good news (so far) is that they're asymptomatic. I'm sure a few will pop symptoms if not on this sailing then another. Hopefully transmission goes down soon overall, reducing risk everywhere from Fishlips on the pier to actually on the ship.
Your previous point, about shore leave interactions, is likely just as much a spreader event. I'd also hedge bets on the "mostly vaxxed" passenger model. As much as it sucks that it would put our family in the ineligible to sail column, fully-vaccinated ships are an absolute must for the foreseeable future.