Ekko is not assasin and definetly at least slightly overtuned

Simple term: what is assasin - it's high mobility high damage burst character which is squishy Ekko checks all the checkmarks exept squishy. He has dash, blink, and really fast movement speed on passive - it's ok he is assasin He is dealing lots of damage with his spells, passive and items that go well with him ( etc. ) - fine He has AOE stun that gives him pretty big shield and ulty that can literaly heal him back to full health. - serousy? that is no longer assasin that is just mage with lots of damage and mobility....

Like why does Ekko have to be this good?