Finally, we get a hint of what some of the major characters will look like. Keep in mind that this is black-and-white concept art still. Not final versions. Frankly, we won't be able to say much about the quality until we can see the final versions on the final background moving about. Animation is tricky that way. Something that looks great standing still could be horrible in motion, and vice versa.
That said, what I see here strongly reminds me of the old Hanna-Barbera stuff from the 80's. No, not the wonky Captain Caveman much loved by the Trollwife, but the more realistic, "dramatic" shapes. Anyone worried about a strong anime influence can probably relax. Not an oversized eye to be seen. And I'm not seeing much toy-manufacturer influence either; the weapons are properly proportioned to the bodies, instead of being oversized and unwieldy. This makes me even more curious about how the characters will move. If I never see anyone do a summersault through the air during a battle scene, I'll be a much happier Troll. ;)