I remember seeing the internet catch fire with people trying to find ways to get these cards without traveling to Japan
Let's say you spent a relatively conservative (based on the number of hours I've spent playing Civilization ) 40 hours playing each game
Bounce effects from Kor Skyfisher, Whitemane Lion, Jeskai Barricade, and Stonecloaker are great for re-casting creature spells
Fixing any color for Pirates means shoehorning three colors is within reach (albeit not something Karsten's math recommends, particularly if you want to have one-drops around)
Enlightened Tutor may get you an enchantment or artifact for a single mana, but you lose a card (the tutor), and you still need to cast said enchantment or artifact
Many players are already decrying the mechanic as too slow, and lacking in adequate payoffs