I agree Jim, Coco Cay pales in comparison to Labadee. I doubt they'll ever put a pier at Coco Cay. It may not be geologically possible.
I recall two times where the swells there caused problems for us. Both times it was fine in the morning when we left, but then things deteriorated during the day and getting back on the ship was hairy, with the tender bouncing up and down at least 18 to 24 inches at the gangway platform. The crew had to time it just right and literally pull passengers off the tender on the up swing.