You might do better to be a very emo Eagle Shapeshifter that dyes their feathers black and insists they are a Raven Shapeshifter, but that nobody understands the pain in their soul.
Sustaining Focus can help you sustain without sucking down -2 all the time. An alternative is to be a Mystic Adept with Heightened Concentration (from Digital Grimoire) which lets you cancel the sustaining penalty.
Honestly, there is not much stopping you from being effective. You can still cast spells in Raven form. The big problem is going to be that as soon as you say Nevermore and reveal you're a mage, you have 0 defense against being shot in the face. So I would say that you more or less want to make a more typical magician, bomb your physical stats (because Shapechange replaces them), go around in Raven form, and fly around Stunbolting people in the face and summoning spirits. However, you really need to find a way to get armor. Would your GM allow you to pay the +50% fee that Sapient Critters pay for some kind of raven-sized armor? If so, you are set.
Things you can cut: if you're going to be Ravening it up, you might as well bomb all your physical attributes but Body (and Body = Raven body -2) since they get reset by Raven Form.
I don't think hardcapping Charisma and Willpower is really worth it - especially not as a 4 edge human. If you really want those stats, you should be a Dwarf.
The value of hardcapping Magic is debatable but it's not an inherently bad move. This would be a place to cut points if you have to.
Astral Combat is useless. The way you "astral combat" people is you stunbolt them in the Astral Form.
Banishing is a trap. The way you banish spirits is Stunbolt. It's really hard to banish things and it does crazy drain to you.
