Xerath W falls in the category "not actually a skillshot before the enemy buys boots", like Lux R and Brand W . If he gets in range to cast it and does so while you auto attack a minion, it **will** hit you.
Xerath Q is more of a skillshot, but a ridiculously easy one to hit. And even if he doesn't hit, he zones you off the wave for 3 seconds while he channels, all the while you're running around like a chicken with its head cut off.
The worst part is when he gets CDR, then he can rotate his spells with hardly any gap in between. Q, E, W, into Q again, rinse and repeat.
it's a lot like Zoe E, remember how everyone was so pissed she can kill you out of the fog of war with no countplay? Xerath's entire kit is basically like that. The skillshots really are not that difficult to land.
. He needs his base damages nerfed. Give him bonus damage to minions if you must.