Each have their own strengths and weaknesses, and I think there's a decent argument for having any of them as your commander: Kitt Kanto, Mayhem Diva is the face commander of the precon and I think is the strongest of the bunch
Each one has the Aura and Role subtypes and the enchant creature ability
A proxy can be issued when the card it replaces meets at least one of these criteria: The card was accidentally damaged or excessively worn in the current tournament (including damaged or misprinted Limited product)
But to make that ability available for just two mana a tiny fraction of what might be available to a player at the time ensures that Time Walk can steal a match in completely unfair ways
Of course, these abilities only benefit equipment decks, but in their element, you've got card advantage and mana speed, rare but appreciated effects for white
While its relatively easy to set up a massive board presence relatively quickly, one board wipe can ruin all of your effort, making it difficult to rebuild