Thought I really liked the prototype Taun Taun pics we've seen anywhere, my mind told me something was off. After checking the film, books and magazines I discovered one big and one medium fails on the sculpt - yeah I know it's still a proto so I hope GG would read this and take a note before its too late.
The main mistake is that the Taun Taun should be smaller (or Luke bigger). Any pic of the full size prop or the stop motion puppet will show that the head of the raider is above the head of the beast. Either Luke, Han when they ride their whole head stands over the Taun Taun's one.
The other aspect that should be corrected is that the Taun Taun legs are much more muscular and thick than on the sculpt, particulary the lower parts. The ones in the figure almost look like chicken ones when compared to the original one.
Escuse me if I sound offensive, that was not my intention. I DO hope GG would read this and make a better Taun Taun for all of us.
In this last pics (the one GG took as reference I'm afraid) the taun-taun head looks to be at the same level as luke, but remember the pic is taken from below the head, and perspective plays a trick making the Taun-taun look taller than it is.