Regular townies turning into spellcasters?

I really hate the don't buy it arguement. I want spellcasters and will probably play them until my fingers are sore but I do also want realistic play at times and saves where this stuff isn't forced on my sims. If people have concerns about it there is nothing wrong with that. For me it sounds easy. I won't go to the Magic Realm on the saves I don't want excess spell casters in. Also they won't practice outside of the Realm on their own.

On topic... I guess I should make sure that I have "played" all the townie sims I don't want the game to pull from. I'd like to know if just favoriting them will work also...