Cass is not short ranged
She basically outranges every ADC, meaning an ADC can't even get within auto attack range of her without completely melting. She is a medium almost long ranged mage with the perfect amount of self peel and MS boosts to kite anything literally not named Riven. And if she's not kiting, she's chasing - and you aren't escaping a Cass that's chasing you.
So let's please stop pretending her lane phase isn't oppressive, that she's this short ranged immobile mage and that her core itemization doesn't make up for the few weaknesses she has. You can be unhappy about her playstyle if you to want be as a Cass main but don't pretend she's weak because that's foolish.
It's like the people who thought DFG was balanced and necessary.