When NCL first started their 7-night Hawaiian programs and had to staff them with an all-American crew, there were tons of problems. Passengers were staying away in masses because of all the complaints.
However, over the last few years things have changed.
First, NCL went to Congress and asked them to give them an exemption to the laws, which was granted. They were allowed to hire up to 40% foreign crew (if my memory serves me correctly).
We went last year expecting a crew that was not up to par with other cruises we've been on, but was pleasantly surprised to find a wonderful crew that was very good. While the ship was nice, the food only so-so, the staff was a highlight of our cruise.
But quite frankly, like most people, we didn't take this for the cruise, we took it to see the ports. And as long as you go on this ship with that expectation, you'll have a wonderful time.
As for gratuities, NCL calls them a 'fixed service charge', which is automatically added to your onboard account in the amount of $12 per person per day. The reason they call it a service charge is to encourage you to leave additional 'tips'. To me, making it a mandatory fee is not right. Gratuities should be optional. When they are made mandatory, then they should be a part of the cruise and advertised in the price.