It has come to my attention that you can now assign magic to be used on any item. This can pose a problem if you put it to a weapon - say the Arrow.
Scenario 1
So you got the Golden Arrows. So it takes Magic. So you are out of Magic, now you can't use the Golden Arrows until you get more magic power, thus you can't use Arrows. Period.
Scenario 2
You upgraded the Magic Sword. It now is twice as strong, but only if you have enough magic. You run out of Magic, and thus, can't use your sword... In the middle of your fight with Ganon. Ganon destroys you.
Conclusion
See? Giving the ability to use magic to items that you can't use downgraded forms of can be risky in a quest.
Quest rule
If Item allows, use a downgraded version of the weapon you have if your out of magic.
This rule would enable you to play through the above scenarios without any problems.
Thoughts?