Good shot! But on the technical side, 200mm and crop sensor = 320mm FF equivalent which is even more sensitive. 1/800s at 320mm is basically the same as 1/500s at 200mm, so in fact you're kinda proving the point that 1/500s is enough at 200mm

In terms of the blur, all what matters is the angular speed. Say a 100m sprinter does roughly 10m a second, shooting at 1/500s from the side when he's moving perpendicularly to your line of sight, he'll pass 2cm in 1/500s, so it's a bit too much. But even 1/2000s won't be enough (he'll make 0.5cm in 1/2000s).

However if you shoot say at 1/500s and 15 degrees along his movement direction, 2cm turn into 2 * sin( 15 degrees ) = 0.51 cm, as if you were shooting at 1/2000s in the first example. So changing the angle from 90 to 15 degrees is like adding 2 stops of freedom.

Anyway, whatever the speed is, panning helps compensate that, but a good IS will help you with panning. Panning handheld without IS isn't that efficient.