I just gotta point out that it's quite challenging but you can very consistently do any wall combo on Cassie.
However if this WASN'T the case, him saying that it's fair for Sub to have his options restricted and his BnB's damage cut in half, because his Clone restricts other characters options, is another new level of silliness. He's already balanced around the Clone and his damage reflects it, cutting it in half again would NOT make him "more" balanced especially not in this match up, and as such only proves your point.
However it CAN be done so he's right, he's just driving the wrong points here.