There's really not much math in it, the biggest requirement is for creativity. Need to think up ways to use spells fairly quickly. That does get easier with practice.
As for the mechanics, there are some cheat sheets here which may help.
Well said. As a gamer in Mage (WoD) for a long time, it wasn't too hard a leap for me to grasp the idea of letting role-playing drive the magic system, but having played plenty of other systems, I can see where some people might be intimidated.
To me the spellcasting in DFRPG falls somewhere between Mage and Shadowrun (both of which I love).
Mechanically it really is pretty simple. I highly recommend all players, and GM's with wizard concerns take a little time reviewing the rules and those cheat sheets, and then most importantly doing some test rolling/simulations.
That's what I did, and much like any math class will teach you, a handful of simple repetitions will learn ya pretty quick.
Then you can settle in to the fun and creativity of being a
clever wizard without worrying about the mechanisms.
Also, I tend to encourage matching discipline and convictions skill levels for new wizards. Helps cut down a bit of math and gives the player a "safe zone" of casting that they can easily get a handle on.
Creativity over math skills make for a good wizard player. In our game, we have one Wizard and one PC with Sponsored Magic. In a nutshell the players say "I do this" and I tell them how much power that will take and the difficulty for the casting roll. Simple as that.
And
THIS!
Given the role-play, collaborative nature of the Fate system, the biggest concern should probably be what's cool for the role-playing. The GM can fudge the machinery as much as he/she likes to accommodate a really cool idea the player comes up with.
If there is any rules-lawyer concerns, just have the GM discuss with everyone how flexible he/she is going to be in adjudicating magic right at the start, hash out any concerns, and then run with it.
I tell my folks that if they can come up with something awesome and reasonably feasible, I'll invent a roll if I have to in order to give them a shot at it. We've always played it pretty pliable where rules are concerned. Role-playing comes first.