Actually, I love the lunar phase idea, its a great way to make enchanting a little more predictable, like damage enchantments during a new moon, or a more likely fortune enchantment during a full moon, etc. Seems like an obvious thing to me- BUT (and I'm not really a complainer; however...)
Yeah, the half round, half square moon looks pretty misguided. Someone made a square/rectangular moon phase graphic set, I would love to see that implemented. It was really good.