Theres no reason to pick Xerath
Hes an Artilery Mage. A type of Mage which already has the least amounts of champions in its type. I could only list a few. And all of them does something that xerath does not. Lets see: ☆Velkoz deals true dmg ☆Lux has a shield for her team ☆Ziggs can destroy turrets Theese are adcs but can be played as an artilery mage ☆Varus deals phisycal dmg and safer to play ☆Jhin has bigger range and deals phisical dmg also less safer than varus. So its really not worth to pick him. Also assasins kill him in less than a second and he cant do anything about them.