I'd have to go with Carnival Victory on that one. Dominica is definitely one of my favorite ports, and St. Kitts is a great one, too. I believe that the Victory is a newer ship. The Victory is a larger ship than the Serenade.
I'll be on the Caribbean in a couple of weeks. I would imagine it will be similar to the Emerald, but will take a bunch of pictures and post them when I get back. Here are the pictures from the Emerald. Tortola is a great island. We've done 2 catamaran sail/snorkels there, both went over to Norman's Island area. One had a cave and one was around a rock formation like the pitons in St. Lucia. We had a cab driver take us around the island for $20. He took us to a restaurant that over looked where the Caribbean and the Atlantic met, it was breath-taking. Then he took us to a real nice beach on the northwest side of the island. It was gorgeous. He showed us where Jimmy Buffet wrote "Cheeseburger in Paradise". I know the Caribbean Princess has the Skywalker lounge, which is in my pictures of the Emerald. I don't think it has the Sanctuary, but it does have the MUTS (movies under the stars). This upcoming cruise is only a 3 day cruise, so I won't get to check everything out on board, but I'll do my best to try as much as I can.
Tortola seems very beautiful. I guess I'm just scared that the Princess ship might be too quiet for us. Am I crazy to think that? After ready a few bad reviews over the Carnival Victory I'm leaning more towards Royal Caribbean. We're pretty active but Carnival ships sound
Princess, in the Caribbean, for a 7-10 day itinerary will have a younger demographic than on their longer cruises. They have the Skywalker lounge which is their disco and other clubs on board. They don't have the rock wall, the flo-rider, or the ice skating rinks like Royal Caribbean. I don't think you could go wrong with either Royal or Princess. Carnival offers a good product as well, but they usually have a lot more children on board. Not that that's a bad thing. We think Princess is just a bit better than Royal, but that's our own preference. Just to let you know, reviews can be taken with a grain of salt. Usually, the negative reviews are from someone who was looking for compensation for something they felt they deserved a free cruise for, and they didn't receive it. Best wishes!