I don't consider the characters in FF4 to be all that deep. There's some underlying issues with the characters. But you never see them deal with it like in games today. You just have to "imagine" that it's going on. That's the big difference. Characters are more fleshed out and well defined these days. Cecil destroys Rydia's home, yet she never seems to care about that. Compare that to Wakka expressing his feelings and opinions every chance he gets. They both follow blindly. But only one really conveys true character.