Regardless of what setting the game is in, if you are using a priority system of character generation, I am generally against the idea of one priority category being a prerequisite for another category, or one category having a major influence on how good you can get in another category. That makes some categories inherently more desirable than others and essentially punishes players who want to be good at the other category. That's why I think really general things like attributes shouldn't be part of the priority system at all, or at the very least, if you have a magic category among your priorities, it should include everything you need to be good at magic. So if you pick magic as your highest priority, and the setting requires that you be intelligent to be good at magic, then the magic category should automatically include whatever it takes to make your character intelligent in the system—perhaps by giving you free points in the intelligence attribute. Otherwise I'm forced to make my attributes a high priority too, and that skews my ability to make further choices for my priorities (and my remaining attributes). The same arguments would apply if you required a Major Edge in order to work magic, in addition to having a separate magic category. Each priority category should be as independent as possible, in order to make each choice equally desirable and valid for my character.hector in [url=http://www.grandheresyforums.com/viewtopic.php?p=1118#p1118]The Wheel of Time thread[/url] wrote:An Attribute and a Major Edge (or a Minor Edge to be able to learn which should be upgraded to the Major version when they learn how) was the general idea - the Attribute determines the strength of a channeller while the Edge denotes their ability to channel in the first place. The most powerful channellers in the fiction are characters who would most likely be considered NPCs, or are characters who start off unaware of their ability to channel. They would have the Major Edge, but would have the Attribute at 0 - SA expenditure would cover the seemingly random uses of the Power at opportune moments, but they would be otherwise unable to channel. Then, as they receive training in the game, they spend SA points on increasing the Attribute and so become stronger.
To balance out the fact that being able to channel from the outset comes with a Major Edge, most characters in the fiction who are able to channel naturally have a block of some description (Nynaeve can only channel when angry, for example), which would likely count as at least a Minor Flaw, if not a Major Flaw (since it's a hard and fast limit - until the block is broken, the character can't even sense the Power, let alone use it, unless the condition of the block is met).
Anyway, that's a general argument that touches on some of the specifics of what you're talking about here. Things may differ depending on specific settings. Feel free to ignore me and move on.