I didn't attend the VIP day but if my family were to go on a cruise, the Mediterranean would be my first choice. Blue seas, warm breeze, cloudless skies. I love the climate there - a million miles away from the cold old UK.
The first facility that springs to mind would be a crèche, staffed by fully qualified carers. I know that sounds bad if its a family holiday, but my partner and I need a bit of together time and a holiday where we could combine that with having fun with the kids would be worth paying a bit more for.
Other facilities would be a baby area which included a breastfeeding area and some luxury privacy cubicles, creams, lotions, nappies, a lovely supportive health visitor, maybe even baby bathing facilities if some of the cabins don't have baths. Babies don't stop being babies just because you're in the middle of the sea.
In terms of activities it would be good to have a soft play area with a baby friendly bit (can you tell that I've got a baby? :0) and there are cool new things you can get for those places like TVs on the floors which show moving images that they like to crawl on. Also a high tech baby sensory area would be great - something that you don't usually get at home.
A lovely big photo studio where you can go with your baby and mess about and have fun and people take pictures without posing you or putting you under time pressure would be great, and it would also be nice if the photos were very cheap because pretty much all you want to do when you have a baby is get photos of them and lots of people cash in on that.
Speaking of mess, a messy play area (with inbuilt showers) would be great fun - lots of shaving foam, gloop and sand and paint.)
A self service or buffet restaurant would be really useful because if you know your child is going to play up you sometimes just want to eat and run. A restaurant crèche might work well there, maybe positioned in the middle of the room so you can see them, or with video monitors at the tables. And table entertainment would be great. Babies like simple things like lights and mirrors, it needn't be clowns etc.
A library with song and rhyme sessions would be important, a quiet place is really handy when you're on a fairly full on exciting holiday.
And a doctors surgery, though I'm sure you have those already. 