Wanna know why?
Because for him to deal damage he actually has to invest in a lot of BONUS ad.
Also, I see people going on about how he gets "Free" % max Hp damage when in fact going for Rhaast makes you LOSE the FLAT DAMAGE from your primary damage tool.
Reaper's Slash instead deals a % of the Target's maximum health, and it scales off bonus ad as well, having a pretty low base as well.
Similarly, his R has a % max hp scaling and only starts off at 10%. TEN. Without any AD he won't be dealing a lot of damage.
And the most important factor why Kayn won't be like Camille is that when he goes for Rhaast he won't be a huge threat to Squishy enemies.
Rhaast thrives off fighting tanky enemies as he has a lot of tools to survive fighting in the enemy frontline, yet he falls short when it comes to assassinating squshies because he lacks the damage and tools for the job.
In fact, he has to choose which path he'll go down, because each of these forms has clearly defined weaknesses and strengths and he can't change that once he transformed.
And the most important fact of all;
He hasn't even been released yet!
He's on the PBE, wait for him to hit the live servers before making any assumptions about his balance state.
#I'm outta here!