I've been working once again on my Savrolia RPG setting and thought I might tap folk's brains on the subject of magic spells.
There are generally four ways that magic is handled in most game settings. Pre-designed lists that are mostly stagnant (Ex: GURPS, D&D), player designed spells based on a construction method (Ex: Hero), A combination of pre-designed and player designed under guidelines (ex: Ars Magica, Mage), and extreme improvised as cast under a specific style category (ex: BESM, Everway).
Now, for what I'm working on the complete improv method is a no-go. The magic system I'm struggling with is a system of sets of Runes that are inscribed on objects, surfaces or people in various ways that retain energy and can activated to use that energy within the pattern of the rune. Up to now my thoughts were to organize the runes into sets of 20, and a character would buy the set. This was using the pre-constructed set concept of spells.
The question is whether folks would find this too limiting, without enough variation or unrealistic in a fantasy setting. Does it make sense and is it consistent? Is it burdensome to expect GMs to allow the development of new runes (with new or derrivative effects) and be expected to simply use the existing runes as examples on how to develop energy cost, difficulty to create, and effectiveness factors (damage, duration, area of effect)? Should I instead be building more of a constructed method piecemeal thing with examples?
Part of the reasoning behind lists is it makes character creation go faster for players. Additionally it gives a GM a good solid idea of what can and cannot be done with the magic system, for both estimating player potentials and their own design possibilities within plotline. But at the same time it does limit outcome.
Input on this would be appreciated.