[@King Cosmos]
Magic Analysis does make it easier to learn the spell, but only in the same way that understanding of a subject makes further study of that subject easier. You won't automatically learn a spell by analyzing it.

You CAN learn other spells from any creature or, later on, maybe even any "class." The EFFECTIVENESS of those spells, however, and several other factors, will determine how useful those spells are to you and your "role." For instance, Jason the Slime has learned Stone Shot. A Slime doesn't have as much MP as a Wisp, so Jason can only use Stone Shot twice before he runs out. A Wisp that learned that same skill/spell, however, would be able to use it 3 times because they have more MP. However, Stone Shot itself is weaker than Mana Orb and requires that one actually has a stone in their inventory to shoot. So the functionality of the spell might depend on whether or not you're in an environment where stones can be easily acquired.

It's just like real life--you can learn any skill you put your mind to even if you're not "naturally talented" at it. But Bruce Lee does not fear the man who knows 10,000 kicks. He fears the man who has practiced one kick 10,000 times. And he'd probably shit his pants at the guy who has practiced one kick 10,000 times in 10,000 different applications.