Paul, At least half the crew on the Divina when it sailed from Venice were from the Poesia who had done the previous years transatlantic cruise and had worked the caribbean previously.
Friends who were on the ship told us their waiter in the Black Crab spoke very little English and they had a bad time trying to make him understand what they wanted to order.
We were lucky to have a great waiter from India called Steven, our waiter from the Poesia last year Wayan was also in the same dining room, anyone who is lucky enough to have either of these guys will not go wrong.
Apart from the waiter issue there is also the kitchen issue, one serves both the Black Crab and Villa Rossa while the other serves just the Black Crab on the other floor! that may well explain some of the slow service along with the fact that assistant waiters are always off bringing drinks while the waiter does everything else.