A few days ago, on the Asatru UK facebook group, someone took issue with the focus of the next great heathen gathering being the goddess Hel. They seemed very offended by this and accused the group of being "Rokkatru" for paying homage to the ruler of the underworld. Rokkatru are heathens whose primary focus are the beings associated with "darkness" or the underworld. Some of these might be considered antagonists in the story of Ragnarok. Such beings are Hel, Jormungandr, Fenris, Surt and the often maligned Loki.
The complainant seemed to be saying that, in heathenry there are "good" beings to worship and "bad" beings that should be shunned for some reason. This conveniently ignores the fact that many of the "good" gods are less than perfect. Thor certainly has anger management issues and has been known to break frith at a whim. Odin is very far from a good guy, betraying his followers and acting in a very rapey manner in more than one instance.
I think this desire to categorise characters and beings from the mythology as either "good" or "bad" is a hangover from christianity. In christian doctrine, everything is divided between "that which is of god" and "that which is not of god". Further, everything to do with god is good and everything that isn't to do with god is bad. To polarise this yet more there is no neutral or null position. If you aren't on god's side, worshipping god (in the correct manner) then you are "not of god" and thereby evil. There is little to distinguish a satanist from an atheist - they will both suffer in perdition.
Heathenry isn't like that. While there is a "battle" between gods and giants, it isn't as simple as polar opposite ideologies fighting for dominance. Many beings that we think of as gods and goddesses have Jotun parentage - Odin, Thor and Loki being notable examples. No-one would question anyone's right to worship Skadi, yet she is fully Jotun. So it is not as simple as the Aesir and Vanir being 100% good and Jotuns being 100% evil. Clearly these two cultures have interacted peacefully at times. Indeed, it seems that as Christianity took sway, Jotuns were demonised to better fit the church's narrative.
Similar demonisation may have occurred with Loki. Always a bone of contention with some heathens, a fact I'm sure that he appreciates, Loki is often viewed as "the heathen devil" or similar. He's a bad guy, surely? He fights on the "wrong side" at Ragnarok, so he must be a wrong'un. But Loki would never allow himself to be so easily labelled. Rather than "the heathen devil" or the rather reductionist term "trickster god", I think he works better as an antagonist or agent of change. It is difficult to grow or improve without some kind of challenge or hardship to overcome. Loki embodies that and more - he will shake up your life to force you to see the world in a different, more useful light.
Loki is blood-brother of Odin. Odin isn't anyone else's blood brother, so there must have been something particular that ol' One Eye saw in the son of Laufey that, at the very least, was useful to him. After all, without Loki, Odin would not have Sleipnir. In Loki's travels with Thor, we also see how useful his moral ambiguity and transgressive nature can be - Thor certainly wouldn't have Mjolnir without Loki's willingness to dress himself (and Thor) as member of the opposite sex.
There is no pure good and evil in heathenry. Everything is nuance and shades of grey. Just because Odin does it, doesn't make it good. Just because something comes from a Jotun, doesn't make it bad. This appreciation of the darkness in light and the lightness in dark is key to the full and proper appreciation of the heathen path.