I know 3 and 4 both have aspects of them that contradict the lore established in previous games or are otherwise a bit nonsensical. One thing that I'm kinda split on is how the Brotherhood of Steel is depicted in the later games. Now, I've never played 4 or Tactics, so my knowledge is limited in that regard. I do feel that the idea of a splinter faction that chooses to help people and be more inclusive rather than horde technology and deny access to outsiders isn't a bad one. Really, the only thing I'm not too clear on is how they were able to travel from one end of the United States to the other. I'm aware that in Tactics and in 4 they apparently had airships, which explains how they got to the Midwest and Commonswealth respectively, but I'm wondering how they were able to acquire the tech for that kind of thing. Also, I can't imagine their numbers were so large as to be able to create them, let alone mass produce them. If anyone could clear that up, that would be nice. Otherwise, discuss.