Remove Wizards’ exclusive access to reduced-hunger and hungerless casting. Instead, tie spell hunger to how experienced you are with the spell; this could either track how many times you’ve cast that specific spell, or use your skill in the spell’s school as a proxy for that, or both. Intelligence could remain a factor, but the important thing is that non-wizard casters can also enjoy the benefits. (Note that Wizards, what with casting spells a lot more than other roles and having high spell skill caps, will still reap a larger benefit from this.)