My wife and I took our two children on the Crown Princess last November and they couldn't have been happier with it! They were 4 and 7 and loved the kids area, being treated like royalty by the waitstaff in the dining room, the Movies Under the Stars... The staff in the kids area was great and your kids would be in the activities (Princess Pelicans) which was a plus for our boys.
The only downside to our balcony cabin was that having the bunks down meant that we couldn't combine the bottom beds into a queen. I'm not sure if that would be different in a mini-suite or not.
It's a great itinerary, I heartily recommend it!