I've worked out already that this forum is on a hair-trigger, so I just want to caveat the next question as being legitimate and not seeking to inflame, but when has Marc refused a partner who may show him up?
I thought Casey retired of his own volition?
I also wanted to add that regardless of what anyone may think of Valentino, he is an exceptional rider, however I feel that his rightful place as one of the greats stems from his race craft and competitive longevity.
In terms of being exceptional and great for sheer out and out physics defying speed, beyond what a motorcycle should be capable of, then for me, in no particular order it's Stoner, Saarinen and Marquez