A thing that I think should be noted is non-tiered magic (such as Word of Pain, Pyrokinesis, Quake, etc.) deal MA*10 damage and do not factor Faith. So if you're facing an enemy who has low Faith, your mage still has a viable attack option. Tier II magic deal extra damage and has more AoE.
Also, if you're facing low Faith enemies, use a Magus. Their attack spells deal more damage to enemies who have lower Faith. A Magus with Divinity is a fearsome mage!
Further, feel free to join us on IRC. I'd love to hear about your progress first-hand!