CCL DOES have the speciality restaurants DR. They call them "supper clubs" but basically the same thing. Their steaks are as good as Chops'
CCL has waterslides, golf sims too. As far as the ice skating, waterparks and flowrider, and boxing ring, no. Not sure those make or break a cruise. I saw the ice show, it was nice, but no different than seeing a dance show in my mind.
We decided that the extra cost was not worth it to us. Not to say I would never do an RCCL cruise again, but since we compare everything to CCL since it was our first cruise line, then we really don't need to spend the money.
And Carnival does do desert MUCH better (and not just the C.M.C.) as they seem to have a greater variety of special deserts.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise, Magic 1/14, Freedom x 2 6/14
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013