Syndra's stun isn't dodged - it's missed.
With a very fast cast time, really fast projectile speed, and the range of half the lane with a hitbox which makes Hanzo's arrows seem fair, the stun missing, short of a last-second flash, isn't because you dodged it, but because she missed it. And with one stun allowing her to 100-0 you as early as level 6, there's not much you can feel good about.
Either the hitbox or the projectile speed need to be adjusted to give a reasonable dodging opportunity.
: ^ )