It definitely looks a bit different to the ONE or two pictures that we have got from the books. However I think it is a good representation of a Gourgaz, what can I say I liked it and I will buy at least one.
I also saw the Drakkarim and they also do not follow the early Gary Chalk versions but instead the pictures from the Darklands and the cover of MOM. I personally prefer them and I'm quite happy with the continued evolution of the artwork. At the open day Joe was very taken with the cover of MOM with the new Drakkarim. So I guess he likes them.
I don't see the big deal about the Gourgaz. The book has a single, significant picture and a description of the hulking reptilian creature. To be honest, I feel the head in the picture doesn't look much like anything and froth hides any detail of the jaw. The Mongoose Gourgaz looks good too me, more lizardine or crocodilian than the somewhat ophidian version in Flight from the Dark.