What alignment would you associate with each class

[Trask]

I can see that, though vengeance, no matter how it's couched, has a patina of selfishness that neutrality on the good/evil axis exhibits well. People don't tend to go on an avenging tirade because the guy down the street they've never spoken to was killed by rampaging orcs. It's always* something personal that sets them off.

*I'm happy to modify that to 'almost always' if there are any examples in life or literature where a vengeance streak is started because some random stranger had some misfortune that just set the protagonist off.

Yeah I'd agree with that assessment, the further one goes from Law the more selfish, or at least individualistic, the behavior. The difference between a CG and a CN Avenger to me would be that the CN only cares about getting revenge for their hurts or cathartically soothe their pain, whereas a CG wants to get revenge, and make sure it never happens to anyone else.

Both are selfish enough to see themselves somewhat as the center of the world in varying degrees.