WE do know. It has changed. Twice. More tempering chances per GA and then the scroll was added. So they made a system and then changed it or let it be bypassed at least once. However, they do not see it as a big enough problem and that is why the core tempering has not changed. They want items to brick. ITs part of the journey they said.
So the bottom line is that the players I think by and large think tempering has issues and the devs agreed but not to the point of redesigning the whole thing.