We just ate at Coral Reef on December 19th. We had read varying reviews about this restaurant, but went in with an open mind. This restaurant ended up being our favorite meal of the entire trip. The food was absolutely fantastic! In our party, we had four adults ranging from 29 to 50+ and three kids, ages 5 months, 4 years, and 7 years. Everyone enjoyed their meal, including the non-fish eaters. My husband had the steak and it was SO delicious. I had a shrimp pasta which was also delicious. Another adult in our party had the king crab legs and he still gets giddy when we mention them. They were THAT good! Our waiter was terrific and we also had a wonderful view of the aquarium. Coral reef has now made it to our "must do" list of restaurants when we visit Disney World.
We also visited Ohana for dinner one night. We are big Ohana fans and unfortunately were very disappointed in our meal that night. The meats were all dry and crisp. The appetizers and sides have also changed quite a bit and were nothing great. We have actually taken Ohana off of our list for awhile.
So, I would recommend you go ahead and change the reservation to Coral Reef. I hope you enjoy your meal as much as everyone in our party did. Have a nice trip!