Looking through the artbooks again.
Are there any concept designs that people are particularly sad didn't get chosen as the final one?
I know some people are fond of some of the Ui variants, but in general I think they've done a pretty good job at picking the best designs - I know sometimes when I've seen concept art batches the devs feel like they've went out of their way to pick the worst one, but I really can't see many cases where the choice has been bad, even if I like some of the alternatives.