I thought of this last season and to me this would be infinitely better. This gives mythics and sparks dual purpose and more value. When ya spend all this time farming and/or trading to land a best in slot item, to just end up scrapping it after a blown temper is completely asinine.
With shards to retemper it’ll eliminate that dread of blowing it on such a rare item, but also still makes it meaningful to retemper; its not just a giveme, it takes something of value to do it.
Anyway, I think it’s worth looking at more or testing it out.