I think a big factor as well, on the meta side of things, is that the majority of the Legion's planned content was cut in order to get the game out on schedule. Most people don't even notice because people don't usually side with them (nor have I, even though I've lost count of my number of play-throughs), but their whole side of the map is almost empty, and even the Brotherhood has more faction quests and everything. I think if that hadn't happened, we would have seen a much more fleshed-out and interesting faction, and questions like this would be explained.