For reasons not worth getting into, a few years ago, I found myself in a cathedral in West Virginia. It was new and, in the manner of Catholic churches that follow ancient standards--few though they may be--it was impressive. The space was big, the proportions were right. There was just one problem: it was the tackiest, gaudiest church I had ever been in. Much of the interior was done in a combination of pastels and bright colors, and every last bit of space was filled with something designed to draw the eye. It looked not unlike how Socrates describes democracy in Book VIII of the Republic: the face of a woman in a statue where every element is made to perfection, at the cost of any coherent organization of the whole. It was, as W.H. Auden used to note, the sort of thing that would make any Christian wish the iconoclasts had won.
This is also, apparently, what is happening to Chartres during its restoration. Gothic architecture was notorious for polychroming everything, and the nicer the church, the more likely it was to be filled with endless amount of gold-set and jewel-encrusted trinkets. Over time, the polychroming came off; after the French revolution, most of the trinkets, crucifixes, reliquaries, and the rest disappeared from public view. Additionally, many gothic churches underwent substantial reconstruction in the mid-19th century; Victor Hugo's Notre Dame de Paris is a clever advertisement for restoring the façade of the cathedral wrapped around a story about a poor woman and a hunchback.
The objection requires believing that the original design of the church is offensive to the eye which, to be fair, it is, and that the architecture--including the windows--represents the 'real' or 'true' design from which the decoration must be considered an unfortunate, if natal, error. Time and history corrected the mistake. In this sense, neogothic architecture learned a lesson that the original gothic architects and artisans never intended to teach.
When I was in Paris, and visiting St. Denis, I had an awareness of how really wonderful the space is: the intention Abbot Suger put into the design, the way the individual elements, each an innovation, create a space that is much more than the sum of its parts. But I also knew that had I seen it 300 years before, or at any other time between its inception and the Revolution, I would have hated it. What I saw was, in fact, only made possible by the Revolution that stripped the church of its least appropriate aesthetic elements. People like to look at gothic architecture and think that it has stood as it was for a thousand years; people deride neogothic architecture because it looks too new, but that façade at Notre Dame is perhaps 80 years older than the gothic buildings at Princeton. It looks like what we have reason to believe it looked like at some time before, minus a few details.
I sometimes wonder if the objection is not to any of the renovations except inasmuch as they no longer allow you to feel that magnificent, false feeling of standing someplace unchanged for a millennium.