I think this would introduce a new way to play as well as giving incentive to add more character slots. The sun, moon, star, and even shadow schools could be added as new starting schools. I can think of a ton of ways this could be implemented. It would give way for more story and quest elements and give a "behind the scenes" look into the astral and shadow schools. Shrike, Seraph, Sentinel, Nova, Herald, and Fiend could all stay quest-locked in Khrysalis as they could still be 92 and 97 respectively. With the addition of these schools as starting schools you could add new spells entirely, and even "borrow" some of the other schools but adjust the damage to incorporate the school change. Such as when bosses cast shadow versions of other school spells or even star, moon, and sun versions of them.
