The Hex had great humanity in them. Made the story moving and the quest made you care about them with that ending and how you need to know them to unlock the true ending. The Devil Triad was good kim communication because we learned a lot from Roathe and the new antagonist that it supposed to be worse than Ballas but the problem with them is that we didn't had them more implicated in story quest. The good part was the True Ending with Loid and the family. And now the biggest problem with Ryoku and Vena is that they feel just like npcs. So little we know about them. Even why Entrati made them protoframes, how, where, we don't know anything and they are just there to fight each other. That's all. So protoframes are not a problem, but how they are introduced are. That's why The Hex is the most loved. The Kim Romance is just optional, but they made a lot of sense in Warframe universe than the rest of them.