I think $15 is the price if you're in a suite, so it probably went up from $14 or something. Normal cabins are $13.50, up from $12.95.
The big ones are:
--Room service is no longer free, there is a $7.95 flat order fee for anything but continental breakfast (which is still free)
--Gratuity charges mentioned above (Basically they have increased a total of $1.50/day in 2015.)
--They keep shuffling around things with the upcharge dining venues. (Which package includes what, and possibly some of them will also go to a la carte pricing, but that won't affect people who already have dining packages? Or something?) And an auto-gratuity added to the upcharge restaurants.
In total it doesn't add up to very much, esp. not when you consider the cost vs DCL, and the food stuff doesn't affect any of the current complimentary dining. I think it's more a matter of the fact that there's a new CEO and he's being kind of spasmodic with his changes. At one point he decided people weren't allowed to take food from the buffet to their rooms (right after the room service fee was enacted), but that only lasted about two weeks due to outrage.
I didn't feel terribly 'nickel and dimed' on NCL; I paid extra for the same things I would pay extra for on DCL (internet access and a spa thermal suite pass). They *advertised* things like upcharge dining and shows in the daily activity guide, but no one acted like I was doing anything wrong by not buying them, and no one ever tried to sell me anything. I interacted with the spa desk staff at least twice a day for a week (to get into the thermal suite) and they never tried to sell me so much as a shampoo and blowout.
(Additionally, I was in a solo studio that was steps away from a free refreshment lounge (solo only), so i had all the beverage and caffeine I needed, even free espresso drinks.)