Anyone find kha'zix's damage underwelming

I tried him because I was trying shit out and what ended up happeningwas I felt weak and I wasn't feeding. (Another thing I didn't notice until now is the removed the auto stealth in bushes for his evolved r. I thought it was a cool mechanic but I didn't know it was gone until now). Anyways I was able to kill their Kayle after I got a couple kills and you who I'm lucky forgot smite but before that, I didn't really do damage. I was unable to oneshot kog'maw all game. Our tritsana was doing better luckily and we won. So is does kha'zix's have bad damage for an assasin.