I have the loot off Drentik the Mad with "minion of eternity", and it works just fine on all of my shaman pets. While not as potent a focus for the other classes, and a lack of experimenting with this particular pet focus(minion of dischord), it does produce the most power pet possible for me every time, and I suspect it tampers with other effects on the pet as well, such as attack, and to a minor extent, some hitpoints and relative base value statistics.
My pet seems to land quads a bit more frequently as well, and loged dps through yaulp show this to be fact, not fiction.
Therefore, if the intent by SoE to remove this aug since being a pet focii of all/all status to preserve pet class focii for only pet classes, this would be, and is, incorrect.
It is quite possible however,that at the time of this expantion, this were to be the case, but to all my fellow shaman rejoice, as it is no longer.