I know someone asked this Q a while ago and I wanted to think about it before I answered. But my search-fu is not as powerful as I thought it was and I cannot find the thread anymore. So here is it anyway.
IMO Arcane magic is primal and more powerful in nature in most ways than refined magic [ie the three realms]. Arcane can tap into the elements, weather, earth nodes and other abilities that are beyond the refined spell caster. For example in my game all summoning requires a ritual and I would let an Arcane caster summon low level things without a ritual.
Now is this more powerful? In some ways yes and in others no. As I would have increased spell failure, increased PP cost as well as the only way to learn would be to have a teacher or trying to self teach. Also the Arcane realm would not have access to the refined spells of the three realms. So no shield or blur spell's as IMO they are refined spells and are not primal enough. I can see an Arcane caster having a wind wall that did the same thing as shield but how they got there is different and it would not be a second rank spell more like a 4-7th with extra abilities like a higher deflecting missiles bonus besides the +25 to DB.
1) As for increased PP that is do to the inexact nature of the spells they just cost more to get the effect you want. They leak so to speak.
2) Also we have all heard the phrase "You can not get there from here!". Or at least I hope you have. That is what is going on with the Arcane realm some spells can be found in the three realms at higher rank [maybe lower PP cost though] but many cannot be refined enough for the 3 realms to cast safely. I might x5 or more the spell failure for a refined caster trying to cast an Arcane spell. I would do the same for the Arcane caster trying to cast a three realms spell but maybe x3 or so instead of the x5, or maybe x1.5 to x3 PP cost for three realms spells.
Well more later but I wanted to get those thoughts down before I slept tonight.
MDC
