I've sailed on the Coral 4 times and love it ... soon to be sailing on her sister ship, the Island, for the 2nd time.
I'd recommend you keep the late traditional dining and speak to the maitre 'd once you get on board about early sitting. The thing about traditional dining is that you can go to anytime dining anytime if you wish. But if you're on anytime dining, you cannot go to traditional.
I've always been pleased with the dining room food, so haven't tried the buffet for dinner - but I do eat there for breakfast and lunch.