Yes, they may need improvement but tearing the creator apart like a pack of rabid, starving wolves won't help him improve much.
I understand we don't want to confuse new spriters but we also don't want to send them back where they came from, never to try spriting ever again.
As for skin tone work, I can recommend this, check all of the GBA games to see what color palettes exist and compile them from there. As for creating new tones I've no advice on the matter.