NOTE:
1. This is my opinion
2. I am NOT suggesting replacing Guar. I know people like them
3. I am not solely talking about mounts. I am talking about the variety of wild life in ESO in general.
As a Dinosaur and Reptile enthusiast, the dino-like creatures and mounts we have so far are...bad. They look like mouths with legs. They look horribly cartoonish nor the least bit interesting.
Also nothing of the guar suggests herbivorous. They look like they have the head of a Snake.
I understand that they had this to work with, but come on.
It's 2018 we have better technology and a better understanding of Dinosaurs. There is so much inspiration waiting to be used.
We get realistic looking horses, wolves, cats, but our dino mounts look like something pulled from a cartoon?
I would take a hadrosaur over a guar.
Also There actually are dinosaur type creatures in Elder Scrolls. Take the Swamp Leviathan for example. It would make a great World Boss, or maybe it would fit better as a Trial Boss.
More Realistically; How about some non-mechanical versions of these guys?
On a side note; the fact that Guar don't look any different in Black Marsh as compared to Morrowind is a perfect example of the homogenization in ESO due to re-purposing assets without doing anything to differentiate them. Maybe give them different skin patterns depending on where they are. They should be adapted to their environment.
Why not use the Tessellated Guar?