I like the idea.
But... it should be something specials, just unique..
If everybody can do it nobody would look to it!!
I mean in my opinion it should be REALY hard to learn how to use magic. and it should be even harder to learn spells. In my opinion you should need to learn each spell, not just learning magic so you can use ALL spells! If you need to learn all spells separately less people will become a mage and that would be good becuase I think 90% of the players will become one.
So: You can train you\'re magic skills, when you have high magical skills you\'re mana will restore faster, spells will do more damage etc. You can upgrade you\'re skills by practice. When you found a scroll with a spell, it will cost like 1-100 hours to learn it! (1 hour for realy easey simple spells and 100 hours for extremely difficult, powerfull, rare, unique spells. When you cast a spell you will lose mana, when you don\'t have enough mana you can\'t cast spells. More powerfull spells will cost more mana. There is another thing, some spells requires you to have an specific amount of magery skills. So powerfull spells can only be learned by good mages.
I think this would balance the game abit, tell me what you think.