I will honestly tell you that the cruise i was on was full of mostly travel agents and a small percentage of the group were from the press.
My honest feeling is that there are some things you can't change on a cruise ship regardless of who is cruising. It is still the same staff and the same food (for the most part).
My personal experience with both Costa and MSC now (I tried both this year), is that most service people were very nice and I thought the food was better than I expected (I had heard horror stories).
I think the worst part of the experience is the other passengers being mostly European. I think Europeans in general are not as nice to Americans as we are to each other. It is not as if they are working while onboard - they are on vacation.
My gut tells me the Italians are not any nicer to the Germans than they are to us, however. I think the European way is just to be a bit more impersonal.
I also think the service people are not trained to work for tips if they are European. But many of the people on Costa are now Asian.
In any case - the thing about both of these lines is that you are in a foreign country when you are on these ships, which is different than a US-cruise line. On Carnival (for example) it is like being in America no matter where the ship goes. On MSC or Costa, you are essentially in Italy and they act differently than we do. They are a bit brash, loud, drink & smoke, etc...
I still say the staff I encountered were all very nice to me, however, as long as I made an effort to talk to them. But if you just sit back and observe, you might find them a little course for cruisers. They don't tend to think of cruising as being the same "special" experience that we do. They didnt start cruising back when it was elegant. By the time most Europeans started cruising it was already starting to get more casual...
I hope this makes sense. I am trying to validate what you guys are saying, I don't disagree with you. I am just saying it is a little like saying "New Yorkers are rude." - Yes, they seem rude and they kind of act rude, but if you talk to them they are generally nice and sincere people. They just treat strangers differently than the average Americans do.