I have cruised twice since being diagnosed with Celiac's. Both of those were on Carnival and I was very happy at how they accommodated me. I could usually figure things out on my own but when in doubt the waiters and Lido staff would either answer my question or "Ask". I never had a problem.
I'm glad they are putting more emphasis on Gluten Free. For me it's a requirement but many people are making it a lifestyle. I do feel it's sort of the "Atkins" of today and will gradually fade out but for now I'm happy with the emphasis on Gluten Free and how the cruise lines are addressing it.
My Father-In-Law also had Celiac's and he had a real problem with dining out and cruising. Ten years ago when we cruised with him the staff had no idea what "gluten free" was and I did most of the choosing of his food. I'm glad this has changed.