Sure, a lot of the characters could have had more screentime, but really the main characters were developed fine throughout the game. I mean there's only so much they can fit in until they start overloading with information and trying to cram too much in -- after all they still need to follow structure within the story.

A good example, even though I love the game, is that most people complain about Chrono Cross for trying to cram in so many characters and develop them too much.

However, in saying that, I will agree that Lani would have benefited more with further screentime and development. When I first played I thought she'd really have something deep with Amarant, and it would have been nice to explore that.