That's an interesting point - Perhaps symbolic indicators of being harbingers of a greater expansive doom coming in their wake rather than being primary antagonists themselves, heralds of destruction as it were?
I personally like this idea^^
Now I've heard that they are somehow related to Grand Admiral Thrawn but I'm wondering if that's not a red herring. Perhaps they represent some other Force entity on the verge of returning?
I have to admit that I'm looking forward to this show (I'm just hoping that it's not the disappointment that "Obi-Wan" was /sigh).