I like the idea of specializing having some advantages and disadvantages. Ideally spells/skills of a particular school will cost less AP to cast and be more powerful at the cost of more AP to cast spells/skills you are not specialized in as well as those spells/skills not being as powerful. The choice to specialize being up to the player of course and not a required thing if you want to be a jack of all trades (you just don't enjoy any particular advantages with those spells/skills if not specialized.)
