Quote Originally Posted by Optimystik View Post
The problem is that the high-tier classes tend to be prepared casters. Well, what do all prepared casters have in common? They get their powers through study.

Joe commoner with 18 Int can pick up a book on magical theory and puzzle his way into wizardry. Heck, if he's that smart he could even work out the basics on his own, without said tome.

There isn't much in-universe justification for smart people not being smart. The fact that wizardry is even possible means that sufficiently educated people can unlock its secrets - and once they do, they can teach others. The Theory of Relativity was very difficult to come up with, but much easier to explain to others once figured out. It's a lot easier to restrict favored souls, sorcerers etc. because you can simply say "there are no dragon-descended or celestial-favored people in my setting." But saying "only a few people can study X, no matter how many smart people there are" is a bit less realistic.
Sure, any smart person can grasp Relativity now.

But it's easy to see why magic wouldn't be like that. You can easily see why it could require savant-like abilities. Which are rare in RL. Very rare. And having the knack for all of the types would be even more rare.

Making it believable.