I agree, the 11 footer is in need of another restoration, one that will bring it back to 1967.
That will NEVER happen.
To begin with, what I've read suggests that details were added to the model up through the end of production on the Original Series in 1969.
Secondly, there are no reliable, detailed, high resolution color photos of the model as it existed at the end of the original series. Remember (a few posts above), Miarecki was working off of black and white photos! There are subtleties and shades of color that will probably never be reproduced because the quality reference material just doesn't exist.
NASM had the chance to photograph and document the model in full-color detail when they received it in 1974 but it never occurred to them to do so.
I agree that Miarecki overdid the shading on the model and that the present paintjob ranges from 'okay' to 'hideous' depending on your attachment to the Original Series. What the model needs before repainting is touch-up on worn decals, some fill-in and structural strengthening in areas where cracks are starting to form, and a better place to display it than the ground floor of the NASM gift shop! It might even be nice if they at least lit the model's lights for a few minutes a day at the start of open public hours.
Whether most people like STAR TREK or not, the USS Enterprise is an icon and deserves to be treated and displayed better than what the Smithsonian has managed for the better part of 40 years now.
Granted, the Smithsonian has its own budget crunches that it has to live within and a model may not get the priority that say a real-life spaceship or rocketsled would... HOWEVER, it's still an artifact of American pop culture history and inspired several generations of engineers and astronauts.
I'm afraid that most of the Powers-That-Be at the Smithsonian may not share that point of view or even be cognizant of it. Remember, these are the guys that royally !@#$%@#$@ed up the display of the Enola Gay around 20 years ago... That may have been another administration that was responsible for that foul-up but the politics and nonsense still exists for many things that the Smithsonian chooses to display or hold in storage from public view. They have other STAR TREK models and memorabilia that has not been on display since the mid-1990s...