While I think this design is absolutely beautiful, the lips are too human-like. On a thematic level it works of course, prisoners (or monks) who haven't seen a woman in years would be seduced by anything that looks remotely female. On the other hand, it wouldn't make much sense that this alien would suddenly develop very human lips, especially since it comes from a dog/ox. It's an aesthetic that can't be explained by the rules of the universe, so I'm glad that they went for a more traditional looking mouth. I think the ADI guys made a perfect compromise between the classic design and Giger's redesign. What they came up with is the best looking alien since the original!