Doing stance change while mashing the throw button allows to tech any throw and at the same time you can either block low by holding down ( or you can block with back in case of overhead ) , pretty much an OS wich kinda eliminates the attack/throw mixup and you would do this whenever you would block anyways.
Some do view OS as lame , personally i don't think this breaks the game but i can see some characters mixup potential being reduced with this.
I'm assuming that they're going to remove the throw tech when you're in the stance change animation , can't tell you more.