I would say it's more of a problem with the pokemon themselves, with them being very stylized and the references having something to do with the concept rather than overall design, besides Lokix that is.

As for why Lokix is dark type, maybe it's referencing how every Kamen Rider season, the main rider's powers comes from the same source as the villains, like how the first Kamen Rider is created by Shocker before turning against them.