I've pretty much played nothing but Arcana Unearthed/Evolved since about 2003, so this is my kinda topic
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My suggestions:
1.) Multiclassing is tempting, but you really have to consider what you might be giving up at higher levels. For instance, one of the Champion of Knowledge's coolest abilities comes at 15th level, so you have to consider how long this campaign is going to last, what level it's going to start, and if any of the high-level abilties appeal to you. This is mostly dependent on the rest of your group, of course.
2.) Dracha make decent Champions, provided that the class abilities of the Cause don't rely upon Charisma. Knowledge is definately a good choice.
3.) Taking all six Dracha racial levels is tempting, but in my experience, those levels completely define the character. Once you have perfect flight, a breath weapon, bite, and claw attacks, you're effectively a medium sized Dragon that happened to pick up some levels here or there. If you're a fighter-type this usually isn't a hindrance, but it can be crippling if your class has abilities dependent on your class level.
4.) Verrik Greenbonds...sigh. While mechanically strong, Greenbond is supposed to be the rarest class among the Verrik, and yet that +2 Wisdom means that it's one of the most common player concepts. If you decide to go with this, I'd advocate avoiding the tree-hugger stereotype and find some more esoteric and philosophical reason for a Verrik to choose the power of nature. IMC, the Greenbond eventually multiclassed with Akashic and took the Physician prestige class as he went from a mystical curiosity about nature to a more clinical, scientific analysis of what makes life tick. Mechanically, you might find some advantage in picking up a single level in a martial class to give you heavy armor and martial weapons, since your spells are all verbal-only. A Greenbond with a single level of Warmain can pretty well emulate the Cleric's Heavy-Armor-Healer routine. As a Verrik, remember that you get expanded access to complex psionic spells, which gives you a considerable ability to shut down individual foes.
5.) Having played a Loresong Faen Magister from levels 1-20, I can tell you that it's a very dynamic experience. Unlike a D&D Wizard, you can heal, and I've found that was my primary function at lower levels. It's not until you gain access to 3rd level spells that "Blast-it" Magic becomes practical, so expect to play a support role early on.
6.) As a spellcaster, Feats are your friends. Brandish Magical Might and Modify Spell are all considered "no brainer" feats for a spellcaster, although in practice, you can probably get by without them up till 10th level (at which point Quicken Spell becomes the real no-brainer, and spellcasting really hits it's stride). For me, Blessed Mage is also good for any spellcaster who finds himself in a healing role. Being able to cast healing spells at a 25' range is incredibly useful for alternating between healing and your other combat tactics without losing actions to move up to the wounded, and then back to safe spell-chucking range.
As a Greenbond, you more or less have Healing in the bag, so I would focus the rest of your spellcasting resources on spells that control the battlefield rather than blow things up. Muddy Ground + Eldritch Web will rapidly turn combat into a quagmire as every foe passing through the overlapping area of both spells must make balance checks to take any action, and any movement provokes a reflex save to avoid the web. Couple this with mind-affecting spells from your Verrik racial access, and you can effectively go about shutting down the enemy so that the rest of the party can pick them off. If your party lacks another caster, pick up Complex Spell level 3 for Flight, Invisibility, and Dispel Magic, and consider nabbing Complex 5 and 6 as well for Teleport and some other goodies. Elemental Mage is also not a terrible idea to pick up.
As a Magister, you pretty much have free reign with the entire spell system. If you're looking to expand your spell access, consider investing ranks in the appropriate knowledges and qualify for multiple Racial Templates, particularly Sibeccai, Dragon and Fey. (remember that Loresong evolved levels only give you access to the Fey template, not improved access to fey descriptor spells, which only comes from the feat.) If you want to be a sneaky, mind-affecting type, try Fey Mage, Psion, and Elemental Mage Air to make the most of being unseen. For a Blast-It Mage, try any combo of Energy Mage feats with Modify Spell, Brandish Magical Might, and perhaps Unraveling Mage. For a Buff-Mage or Abjurer, look into Sibeccai and Dragon mage. The sky is the limit when you already have complex spells, and so many exotic spells are just a feat away.
In any case, I hope this helps.
Robert "Addicted to AE" Ranting