Sorry, maybe I didn't state my point clearly. The mage is more powerful because of his versatility in spell selection, with a Wish or rest, he can tailor his spell choices to the exact situation at hand.
A Sorcerer, on the other hand, has to worry about crafty implementation, and using what is on hand.
I like to think of the Sorcerer as the survivalist type, and its the reason why Sorcs are more powerful is that you know beforehand what spells you'll need for most of the game, and have more casting versatility. Mages are like the magic Boy Scouts, they have a spell for every situation.
In literal terms, a Mage is more versatile and powerful by virtue of his spell selection, whereas a Sorcerer may be forced to improvise, and improvisation means he/she does not have the right spell.
Anyways, Dundee, its all semantics anyways. I know the Sorcerer is more powerful, because I have experience and know the magic system. For those who like to see ALL the neato spell effects, go with a Mage/Wild Mage. First time I tried Spirit Armor, my eyes were popping out of my head.
Good Hunting!!!