We had a similar experience with the buffet. We were on Seaside in May, the MDR service was horrendous with a minimum 2 hour service so we decided to try the buffet. It was a huge disappointment. If you went the first night you would know exactly what would be served the rest of the week. The dishes simply had no imagination and they were unable to maintain any sort of proper service temps. Everything was cold and the few meats they had were dry.
One thing I can count on with Carnival is on the dinner buffet they will have some selections that are also being served in the MDR that evening. MSC does not follow that thought process. I am not a picky eater at all and I left there less than satisfied every night, one night I swear the best thing was the chicken nuggets. It was something I had never experienced on any other cruise line.