Is it ever worth it to go Shadow Assassin Kayn over Rhaast?
I recently got Kayn, and like I always do when I get a new champion, I did some research on their build path, important stats, combos, etc., and a lot of people seem convinced that going Shadow Assassin is a mistake in nearly every game. The consistency provided by the additional spell vamp and CC Rhaast gains seems to outweigh the extra mobility and burst damage Kayn gets by going Shadow Assassin
Is this really the case? Should I bully the only melee enemy in the game to rush Rhaast, even in a game full of ranged squishies? On paper, Shadow Assassin looks really good. Why do people think otherwise?