Just looking again at some of those USS Vengeance concepts: the first one, and several of the more fragmented / skeletal designs, with spiky protrusions coming off them - remind me a lot of the Narada - and I'm wondering if that was something of a basis for these concepts.
After all - the Vengeance looks like she was built in response to the Narada (overly aggressive, larger, and built for war).
Just my musings - nothing concrete, just what these more 'Orc-esque' designs evoke for me, in light of the 2009 movie.
I do like seeing these concepts images: they show an interesting evolution of the Vengeance, and even the more spiky concepts (although right outside the square, so to speak, as far as designs go) still have a place, and are interesting to view, IMO.