IIRC the current format for the Olympic team event is not the original one that was presented by the ISU four years ago. The IOC insisted on some changes. I have forgotten the exact details, but one thing that the IOC required was that the team event would not increase the total number of athletes that they would have to house and feed. The current rules are very clear that alternate athletes are not to be given the key to the Olympic village, although in some circumstances they can sneak in as day trippers for practice.
If the event is a rousing success -- which I believe it will be, especially in the U.S. television market -- then maybe in subsequent years they will be allowed to cast the teams differently.