User blog comment:PerhapsTheOtherOne/Speculative Spitballing: Goliath/@comment-9464517-20150612173646/@comment-24891101-20150613003453

Live: Quite the contrary. While this may be comparatively lazier, the remainder of the Grimm are likewise quite lazy. All of the Grimm are jet-black animals with bits on. These are simply far larger, and thus their bits seem much smaller.

More generally, I remind you that all the Grimm we have seen have casques upon their heads, and scutes on their limbs, as well as similar osteoderms projecting from their backs. Look at a Beowolf or an Ursa. We see the fused osteoderms on the head, on the spine, and on the limbs, just as here. The only reason the Goliaths look so dull is because they have comparatively larger bodies, of which we see the mostly the sides. Neither of the species I mention before have such scutes on the sides. I now refer you to the Boarbatusk. They have more scattered scutes on their sides, but notably no spinal ridge. In contrast, the Goliaths possess both ridge and scattered scutes on their backs. In my mind, the principal reason for the unwarranted accusation of laziness comes from the placement of the ear in the iconic shot above, where people forget the views from the side, demonstrating all their glory. There is no real level of difference in detail between the two, and to represent the Goliath as Live does is to describe all Grimm and poorly.

To me, I think your friends are starting at the wrong end. These are Grimm. They are a natural predator of humanity. Start with that as a basis, and envision what terror they can unleash, bearing in mind war elephants (magnified greatly, for which the Jackson film adaptation of The Lord of the Rings  might be instructive), the necessity of the ankus, and their memory (this in particular given their description). I ask you to look at youtube video of elephants charging, or of cowing predators or of uprooting trees. An elephant roused is terrifying. I would be nearly equally scared of a hippopotamus Grimm. As Seven-Three said, only those unaware of the fury of an elephant dismiss them.