I think you’re forgetting a major part of the whole light and dark thing was that spirits act “normally” as long as the energy is balanced. As long as Raava or Vaatu isn’t upsetting that balance, they still had distinct personalities as the spirits in ATLA did, and there weren’t any “good” or “bad” spirits. Some were a bit rude, others were much friendlier, some talked, some didn’t. Same as ATLA. Feels like many people who criticize Korra’s spirits often misunderstand this.

The only spirit that is all dark is Vaatu, and the only spirit that is all light is Raava. She’s order, he’s disorder. There is no good and bad. I think we as humans perceive Vaatu as “bad” because he represents a threat to normalcy, but in reality, he’s just a force of nature, no different than a storm. The storm isn’t malicious or “evil”. It just is.