All choreography is based on physical ability. You work with what you've got. Midori Ito could deliver certain programs better than anyone else because her massive jumps change the look of the choreography. Sasha Cohen could deliver certain programs better than anyone else because her amazing extension allowed her to create choreography that others couldn't.
Skater's choreography has to fall within the realm of their physical capability, however it is not have to be any one thing---where as jumps have to meet a specific definition. You don't get to decide how you do a flip, an axle, or a lutz. If you do it incorrectly, you lose points. But a technical panel is not going to review how Yuna Kim does her bendy elbow thing in Adios Nonino. Her physical abilities are incidental to that move. Yes there are moves in choreography that only certain skaters can perform. Julia can lift her ankle over her head or whatever. But she's not going to be evaluated on how she performs that move. The evaluation is how that moves relates to the music, and contributes to a program's cohesion.