Well... you can make a Sorcerer into the most powerful Diviner in the world... if you so desire.
*Gasp!* I can cast Farsight 6 times a day!
Or maybe you can roll a dice and let chance choose your spell selection.
I always get this mental image where the Sorcerer wakes up and suddenly a holographic menu of spells appear before him/her, and he/she gets to choose whatever spell he/she desires whenever I level up. 