The other thing I'll say about primal drop rates:

I could stomach the abysmal drop rates more if there was more than 3 things that drop; weapon, charm/totem,... And grade 5 dark matter? It's not like grade 5 dark matter is an uncommon resource, it's a common reward from lvl 40 leves, drops like candy from grade 5 gathering nodes. I have so much of it in storage that I have now taken to immediately vendoring any that shows up in my inventory.

If the primals had drops other than the weapons and charms/totems that made the fight at least feel a little more worthwhile it wouldn't be so frustrating. As it is, you either get lucky, or you basically get to feel like the game is laughing at you by giving you something that is completely worthless.