I think this is the first increase in suggested tips in almost a decade. It's the only real way to get the crew a real increase in salary, because they could pay them double, and it stll wouldn't amount to much.
For those who say they should just pay them a decent wage to begin with, we/you would be paying that amount anyway in higher cruise fares.
This way you still do have "the option" to reduce or remove the gratuities if for some reason the service is really bad. You don't want to reduce those gratuities if there is a non service related issue onboard. That would be punishing the service people for something they can't do anything about.