Kayn's Shadow Assassin Form Needs SOMETHING!

Been playing for most of today, i've played shadow and i've played darkin, i LOVE shadow only because i can move when i hit W and gives me more out play than darkin has. But yes, darkin is 100% better, healing, max HP damage, hard cc, there is no reason NOT to. That being said shadow does have some things that makes me come back too it, that extra damage with passive is nice, but the numbers could go up there. His W becomes his main damage source, with a large range and some GREAT damage, it's kind of the ONLY thing that makes me think about playing shadow assassin > darkin. The way you can fix this is by buffing some of the damage numbers. But yes you may buff assassin, but then you're just making darkin even MORE strong. IMO the way to make it a bit better for kayne's shadow is by giving the Q something like a movement speed buff when you hit a champ and maybe more BASE damage? Maybe then give his ult MISSING HEALTH damage? Make him like an assassin, have him be scary to a lower health target, give shadow form the ability to keep on his target while being able to execute them when they get kind of low. Then just keep darkin form as it is, maybe if shadow form becomes OP try to make it better in darkin form where if he ults someone they will be slowed while kayn is in them? This is all just ways that could allow for kayn's shadow form to have a big use. I don't feel like this will make him OP, as i feel like he is kind of week ATM(this is what I HAVE been seeing, he may be one of the most broken champs in the game and i'm just not seeing it, pls no hate D:).