Magic in Acteos, Land of the Sundered Chronicles

I've been doing a lot of thinking about magic in Acteos, the land of the Sundered Chronicles setting.  I'm largely happy with the standard Vancian spell systems in OSR games, but I feel it needs a few tweaks to fit my vision for the world.

So far, the following are true:

• There is no divine magic.  The original gods are gone, and their replacements don't grant spells to their followers.  Thus, there is no Cleric class.
• The Mage class covers your typical wizard types as well as priests.  All spell casters prepare spells from a spell book.  In fact, the temples and clergies of the ascended gods are the primary body of spell research and training.
• Spells are split into three categories that match alignments: Law, Neutral, and Chaos.  All mages can learn Neutral spells, but must pick Law or Chaos at character creation.
• Outside of the appropriate use of magic by the priesthoods, the practice of magic is illegal.  An agency known as the Emberstorm exists to police the use of magic and is specialized in hunting down rogue mages.
• There isn't anything morally wrong about the use of magic, but it does happen to be illegal regardless of the reason it's used.
• This is also only true in nations that have signed the Emberstorm Treaty and are under such governance.  The Emberstorm does also have agents outside of their jurisdiction that handle powerful mages, which the organization sees as a threat to the safety of all of Acteos.
• I find purely damage dealing spells to be boring, but necessary choices.  Thus, there will be no damage-only spells.  Instead, mages can convert prepared spells into either a healing or damaging effect, as described below.

Healing and Destroying

At first level, all mages must choose to have the ability to Heal or to Destroy.  The mage can convert a prepared spell into either a Healing effect or a Destruction effect depending on their choice.

Heal

The mage can expend a prepared spell to, instead of the spell's normal effect, heal a touched creature for 1d8 points of damage per level of the prepared spell.

Destroy

The mage can expend a prepared spell to, instead of the spell's normal effect, create a destructive blast of arcane energy.  The form of this blast determined by the mage as the spell is cast.

A single target ray or bolt:  Requires a successful attack roll, and deals Xd8 points of damage, where X is equal to the 1 + the prepared spell's level (so, a 2nd level spell converted into a bolt deals 3d8 damage on a hit).  This attack has a range of 60 ft.

An area of effect:  Deals Xd6 damage, where X is equal to the prepared spell's level.  Can take one of the following shapes.

- A 30 ft cone shooting out from the caster's hand.

- A 20 ft radius explosion centered within 60 ft of the caster.

- A 40 ft line shooting out from the caster's hand.

- Other, as approved by the Referee.

This is, of course, a rough idea that has a lot more work to do.  For example, how does the mage determine what type of damage (Fire, Lightning, etc) his destruction effects deal?  Does he have full access to any damage type (which seems too strong), or does he start with a small number of damage types and earn more as he levels (which seems fiddly)?