As for this model, I think it's already an established improvement just by virtue of not having the mane look like straw heaped onto the back. Clearly, great effort has been made to keep the model true to itself while still looking updated, and although I'm a little iffy on the eyes, I'm hopeful that we'll see some variation in that regard. The video is particularly helpful for getting to see it in action. It's a far, far more effective model for conveying emotions via expression - it's hard to imagine seeing a tauren look this expressive, frankly. Seeing the open mouthed belly laugh alone convinces me that this is a far, far improved model in all regards.
In general, I find it much improved - now I just want to see how they do with the female model.
Gallery: New character models
Head on over to the official site and see the process detailed.