I actually don't have a huge problem with that CGI model in The Inner Light, other than they really need to work on the lighting in order to make the ship look more like a physical thing.
One thing that immediately makes it look somewhat off is the overly bright blue light around the outer deflector. It's not like that on the physical ship.
Other than that, it's actually the best CGI model of the 6ft Enterprise that I have ever seen. If they can nail down a few issues that are making the textures look artificial, I would not bat an eye at them 'tastefully' recompositing the existing filmed elements with it in place of the 4 footer.