She doesn't have the kit she needs to thrive. A good kit needs to be fluent, potentially potent, and yet counterable. However, her mobility and conditional CC scream assassin, her Q HP % scaling screams something (anti-tank? AP bruiser?), and her general lack of non-AA damage on R, E, and half of W screams AA Bruiser. However, every area of her kit has been nitpicked to the point that her strengths are generally diminished to nothing, and her weaknesses have become overbearing. Those 3 don't belong in the same kit, as each one makes her potential that much harder to reach. Rarely does someone face the perfect team that has overtankiness to the point that she can assassinate very slowly and not die, and still not be CC'd to death before landing much of her melee-range damage. Before she was adequate enough in all 3 areas to pick one avenue and overbear one or more of these areas. Now she merely must settle for being adequate in whichever area she's needed in most.