I had the idea for a rune system where runes give magical attributes to anything they are put on such as runes of fire, ice or protection. The runes are drawn up in midair to create spells such as a fireball rune or anlghtning bolt rune. The more intricate the design of the rune, the more powerful such as Lightning bolt being simple, but Lightning Bolt Chain Jump is more complicated. As such it not only takes longer to produce, but drains more of the caster's life force. Life force is returned through rest, but they can easily ware themselves out.

That would limit magic use while also giving swords and bows magic capabilities.