All six of SW's killer whales (Ulises, Nakia, Kasatka, Corky, Orkid, and Kalia) are rotated through the daily shows, so it's not a matter of them not being ready to be in shows or not. Trainers have not had opportunities to be in the water with the whales, since the tragic death of their trainer in Florida last February. Since "Believe" focuses on the intimate interactions between the whales and their human counterparts, the show's message is no longer there. They are done with the "Believe" show, and its replacement will debut (hopefully) for Memorial Day weekend 2011. "Believe" and "The Shamu Story" will still run until then, though. Dine with Shamu should be back this spring, too, after the construction being done to Shamu Close Up is completed. (Close Up is drained/closed right now for repairs and installation of acrylic panels that will be a barrier between the Dine patio and the Close Up pool.)
With smaller, off-season crowds, it's too much to run a "Believe" show. It's easier for trainers to give an educational presentation instead -- while they can still work on behavior training during this show. They used this technique with the dolphins because they were being housed in the killer whales' pools during construction of their own stadium. It was a new, unfamiliar environment for the dolphins and pilot whales (let alone the fact that the oceans' top predator...times six!...were sensing them in *their* water! Nervous much?).
SW is an educational park. As far as "The Shamu Story" not being entertaining enough, I think it's fair to say that depends on who's watching. People who want to learn about the animals in SW's care will find it interesting to see what goes on behind the scenes, as it were. It takes HOURS of training to produce the theatrical shows. Taking time to appreciate the effort behind the shows is worth it.