I think the variation in technology and looks has to do with making Nornheim look varied, as apparently it is in the comics. Karnilla is a sorceress, magic to her may look like advanced science to someone else.
if this is a rag tag band of marauders gathered from over time and space, come to reap destruction on Asgard and the 9 reams, that seems like a pretty big villain for the Asgardian's to deal with. So certainly not a small part if that is true. So how does that fit in with everything else we think is going to happen? It doesn't.
how is a rag tag band of marauders gathered over time and space even remotely considered a "kingdom"? as described in the Shepperton Studios information released about that filming, it said it would be a battle between "two kingdoms" when Thor shows up to save the day.
There was also a note in one article Marvel Freshman did about a leader of the "marauder army" apparently requiring a ginger beard. The scenario that makes the most sense for that little tid bit is that the "marauder army" is Vanir. Otherwise, why would a random group of marauders need a leader with a "ginger beard".
If this is a rag tag band of marauders gathered over time and space, where do they keep all their horses? On their spaceship? Because they certainly wouldnt do well on a spaceship with no exercise, poor diet, and no fresh air and sunshine, with a bunch of nasty guys taking care of them.
And what of the guy on the white horse? Again, that's up there with a big red bus with "Moral Sacrifice" on it. A man on a white horse typically means a "good guy", and this guy is on what is a really beautiful *gleaming* white horse, to boot. but he seems to be with the team that is attacking the Asgardians (although it is hard to tell for sure who is fighting who here, I admit, I think all 3 groups are fighting at once, to be honest). And Freyr's description with the horse and the sword fits very well with the guy pictured.
How is gathering a crew of guys over time and space to marauder all over the place exploring the Nine Realms as we've been told will happen? It takes away from that, severely
. There is no reason to add a group like that, there is enough to explore and enough going on without some random group of marauders that in the end mean nothing to the rest of the story.