Aco, my aim is to make it quite exotic, as possibility. On one hand it will be rather difficult and require a significant amount of dedication to learn+educate+execute, while on the other hand I will not make it forbidding, if he wants to get involved with this.
As to the magic, itself, I have decided to create it as a way of magic, somehow "outside" of the weave and rather towards a more mystical way. By that I mean, that it will be some sort of ritualistic way to create a rune (eg, get the ingredients, follow a certain procedure, do it on specific days/nights, etc). This way, I can explain how its step/ritual/procedure draws the mystical power from the elements, spirits, nature and even the weave in order to deliver a certain magical effect, in the form of a rune.
I still have not decided if I will allow permanent runes or not, and even if I do, to what extend those can be, in terms of power.
What I have decided though, is that parts of this type of magical art is going to be lost and/or forbidden by Moradin, in order to follow the changes that happened after the Netheril fall.
Regarding the edition you refer to, I am playing 2nd edition, only.