You could not mimic cloak of shadows with stunts, as one of it's facets is a supernatural ability with no shift value. If you could though, it would be with two stunts which would cost two refresh, because powers are almost exactly twice as powerful as equivalent stunts. This is why pure mortals get extra refresh. Because it costs them twice as much to achieve a remotely similar effect.
Ok, granted. You can however mimic the +2 part and at least partly emulate the see in the dark part (reduce penalties for seeing in the dark by 2). Which actually fits with the point I'm trying to make. Let's take Molly again, the example is quite good for this. If she invokes a regular aspect to hide, you are implying, that she is good at hiding. If she is invoking a magical aspect, you are implying, that she is using magic to hide, vanishing into thin air, as it where. Which is the same thing here. Cloak of shadows costs 1 point of refresh, 2 stunts to emulate it (even if not perfectly) would still give you 1 net refresh, if you don't take anything else. This is the cost of the supernatural component.
But let's compare 2 other things:
Intimidation (Infuriate) vs. Incite Emotion (Emotion-Touch)
Let's take anger here, since that's what infuriate is about. You can take different stunts for different emotions, so it should apply equally.
On a 1 refresh basis, they grant pretty much the same benefit, +2 on your roll to make someone really angry. The only real difference is the source. Infuriate lets you do this, because you are good at pissing people off, Emotion Touch lets you do it, because you have a supernatural affinity to that particular emotion. And precisely at that point, there is the difference: the guy with the stunt gets +2 refresh due to being a pure mortal, the one with Incite Emotion does not, because he has a supernatural power.
Or lets look at Marked by Power. It could be a presence or rapport stunt as well. Only because you know supernatural people doesn't mean you are supernatural. Yet it explicitly is a power, not a stunt, because the supernatural world is an integral part of the character.
Here's the thing. What if I don't want that power? Would you force it on me? Again, it's stifling creativity because you are looking at the RAW instead of the intent behind it.
I'm sorry, but to me it looks like a "want my cake and eat it too" thing. I am able to do (though minor) supernatural feats and take the +2 refresh for being a pure mortal. Choice is one of the big parts of the game, and to me this is one of those choices.
All of this, of course, is for a "regular" game. If you want to play a game particular around the concept of budding wizards, then the OPs concept might work. If everyone has the same benefit, nobody has a benefit really. I would probably still go the "you are no longer a pure mortal" route, and let them progress their powers as they go along or choose to set them aside to become a pure mortal with the appropriate benefit of gaining some refresh (aka free will).
Any system has limits, as UmbraLux pointed out. I'd argue real creativity is working with those limits, rather than pushing them aside when it seems inconvenient.
I personally get more satisfaction out of solving the question of "How do I make this work within the system?" than "What parts of the system can I put aside to make this work?"
I fully agree.
Come to think of it, you could justify a lot, if you tagged a magical aspect on an attack that takes someone out. If a
budding psychomancer is taking someone out in a mental conflict and as a result he enthrals someone, it would be well within the scope of such an aspect, but could not be done by any pure mortal aspect.
