lighting is way too flat.
i think that's what you are suggesting in the title anyways.
aside from that i think that the rider is a little too centered, especially for an action shot like this.
Too centred...? where is he supposed to be when he's in the peak of his trick? If I changed the angle he wouldn't be as centred, but the background would've been to busy... I see what you mean though, I'll find a better angle next time.
Flatty is the trick, not the flat lighting (I don't know what flat lighting is...)