The new elves are great, but they need one or two tweaks.
First is just the ability to compromise. Whenever a peace treaty is made between humans and elves, it should come with certain conditions for each side. Well, okay, mostly the humans. If the elves are losing, the restrictions should be lax. If they're winning, they should be harsh. If the humans don't adhere to these conditions, they risk war, and depending on who would be more likely to win in a war, the elves may or may not retaliate at first, or allow changes to these limitations via diplomacy.
Also, in the middle of the war there should be certain compromises made on each side, really this time, so as to aid the possibility of making peace; The elves handing over corpses instead of eating them, and the usual decrease in tree cutting and animal slaughter for the humans.
Hopefully we'll see these in the diplomacy arc, but until then, I think elves are all but perfect as they are.
Also, I haven't seen anything contradictory in the elvish policies. They believe that animals have as much a right to live as sentient creatures, and as such view the slaughter of the former by the later as just that: A race vastly superior in organization, numbers, and all things to do with war mercilessly slaughtering defenseless races with no provocation.
So, they decide to act in the interests of these animals, being the only race with the means to effectively do so, while also being willing to do so. Because the humans are perfectly capable of defending themselves, and in their minds the ones who initiated the conflict, they have no concerns over going to war with them. And by their traditions, any casualties in this conflict should have their corpses salvaged of all useful resources. Including meat.
As for what they will accept in trades, I'd say that contrary to what one might expect, they'd actually accept crafts made of goblins and other sentient creatures, since they can defend themselves and no doubt had reason to go to war, but not animals, since more often than not it's slaughter as opposed to self defense, and they don't trust the humans to give accurate information. But of course, most of the other sentient races don't make a habit of producing such objects.
As for wood... They just seem to like trees for some reason. Presumably they eat plants, since they have to get food from somewhere, so I suppose it's more likely to be a practical interest than an idealistic one. Forests are the habitat for their animal friends, and whether or not they know it, also do a fair bit of CO2 scrubbing so as to produce breathable air, so maybe that's it. Or maybe it's purely selfish, and they don't like the other races destroying the one biome they know how to live in, and their favored building material.
Not sure why they don't just teach the other races to retrieve wood from trees their way, but rather than outright banning the cutting of trees, it makes sense that they limit the number so as to avoid clear cutting, which is exactly what they do.
Finally, their near suicidal mass assaults... I suppose this is unavoidable with such a long life span, but you'd think they'd limit their number of kids in the interest of population control... I guess they'd rather kill two birds with one stone, in an unusally accurate and ironic way, by using numbers to make up for their reliance on ineffective wooden weaponry and armor in war. Same end result anyway, a more or less constant population... At least, that's probably the idea. The numbers may need to be tweaked a bit for it to reach equillibrium.