I haven't taken what you would regard as a pleasure cruise on a cruise liner. I have, however, been on a lot of cruises: six years in the Australian Navy, a trip to MacQuarie Island sub-Antartica with the Danish Laurtetson Line on the ice-reinfored ship, Nella Dan. And I also spent seven weeks on a 20,000 ton a P & O migrant ship called the TSS Mooltan way back in 1951.
On a big cruise ship the destination is not as important as the facilities on the ship. So long as you're going to traverse nice warm waters, not arctic storms, you'll probably enjoy wherever you go. As it is, most cruise ships stay no more than a day or so at any one location, sometimes only half-a-day, due to the exorbitant costs involved in staying in harbour.
To reiterate, the ship's the thing. Where you go is of secondary importance.