Orcs sound very good, but I wonder if you would enjoy creating mermaids? Sickleyield has a lovely mertail with some addons. I tried it and it works wonders. I guess mermaids would also be interesting as playable characters – even if not many people play them at the time being.
Other creatures I thought about include the Maru, a crocodile-like tribe from The Dark Eye system. I’m afraid there is no content pack that would allow morphing Genesis into a Maru, but I admit I talked about it with DarioFish and he told me it’s interesting, so let’s keep our fingers crossed ;).