Most of the time, the one or two planswalkers of the set and one hyped rare hold most of a given sets financial weight
Unfortunately, this was during Urzas Saga block, the block that made Wizards of the Coast realize that they needed to hire a balance team
As the disruption in Modern has increased in power level, the value of two-mana creatures that dont provide immediate value, like Dark Confidant for example, has decreased, and Leonin Arbiter is no exception
While a bit too fair to be a great maindeck card, Gideon, Ally of Zendikar is a stellar sideboard trump card for fair matchups
It's a powerhouse of flickering fun times, a way to wash a colorless into a color mana needed, a way to turn non-Snow mana into Snow mana, and loads more