Examiners excel at teaching and at demonstrating the "ideal" form. World class skiers are far more fit and do not adhere to that form. For instance, an examiner will have the perfect poling. The world class skier couldn't care less and would just as soon not pole plant, simply powering through the turn and the chosen line with immensely, ahem, quiet, still, stable upper body in the most challenging conditions. The examiner's upper body would likely get thrown. The examiner can overcome the challenge by becoming more fit, then learn how to use that fitness. The world class skier can overcome his or her deficiencies by being empathetic to a guest, and taking clinics on how to teach, from as many sensei's as possible.
Just be aware that there are examiners out there that are world class skiers... Jon Ballou, Paul Lorenz, JF Beallieau, etc... and others who have been current and former nat'l demo team members and olympic medalists (Deb Armstrong, Daniella Ceccarelli) Even Glen Plake has his PSIA L3.