The ultra rare version of shards is up today, 825 or the equivalent of 8.25 diamonds. Only need 3,991 and 3/4 to craft a mythic. So to me, it seems ultra rare AB tasks are meant to provide 2 class xp per battle and not much else.
I’m not as outraged as I was about this. I am still full of rage about a great many things, but not this.