Overall, I REALLY like the Oracle! It's sort of the Cleric version of a Sorcerer, but very much new and interesting at the same time.
One thing that really jumped out at me as I read and then re-read the class though: Focus.
The word focus implies more of an object. In fact, D&D has a pretty strong tradition of Focus items in the game already. In fact, a Divine Focus has already been established as a holy symbol for clerics.
So, I would strongly suggest coming up with a different term for this otherwise excellent class ability.
I would suggest maybe Calling.