Fact is, Latin loanwords, in today's Duden spelled with k, were c-words before the Duden changed the official German spelling. At that point Germany seems to have divided herself from the western world. But was it really Konrad Duden's fault? I have to admit, that I didn't like that man when I started to consult sources, but when I was done, I really loved him. Not, that I shared all his opinions about reforming the German language of his time. But he was not a radical. On the contrary, his argumentation was fairly well-balanced, questioning inconsistency in the spelling of his time in the 1870s: Why spell "Vokal", but on the other hand "Consonant"? His suggestion was not, French and Latin words should all be changed to k-spelling. What he wanted was consistency—either with c or with k. But after all he preferred the k-spelling and at this point I disagree with him. Germany was on an ego trip, heading into the great world wars—and so was their orthography. To hell with the Latin and French heritage, we share with our European sister peoples—"Deutschland, Deutschland über alles!" Konrad Duden didn't try to prevent this, but the last thing he did was to advocate the common right-wing radicalism of the pre-Nazi decades. No, Duden was a fairly modest guy and not at all a loudmouthed nationalist. To me he sounds like he absolutely respected the Romance heritage and their countries of origin. And what later became the official "Duden", was not necessarily all the work of Konrad Duden. He was the moderate who had to negotiate with the German radicalism of his time and the result was the official "Duden".
In the meantime this reform work has been re-reformed several times. And whenever the German government dares to reform the reformed reform, many Germans protest, like the "Duden" had been essentially German for centuries. In fact, the German language, before the Duden became official German dictionary, had made more sense. Generally, I tend to define it the German language before 1850, because the spelling had started to change long before Duden's dictionary was released. People had already begun to prefer k-spelling, although the original c had been standard for many centuries. It was sort of lingual iconoclast of a beginning German nation, which people had been threatened by French invasions since the middle-ages. After having defeated the Sun King and finally Napoleon (together with their English and Dutch allies!) the Germans seemed to have decided to become difficult, naughty and destructive themselves. And before the destruction of two World Wars, they destroyed their own language.
The fallacy behind the first Duden reform, around the year 1900, was the excess of consistency. In English there's no such perfection of consistency, but lots of variation. And variation is just as important as consistency. Too much consistency is a compulsive idea. And still, after several times re-reforming the Duden, the German language isn't really consistent. The modern German language is ruined, that's all. Although most people tend to consider God-given what they once had learned in school, some Germans will understand, that it wasn't a good idea to obscure the spelling of French and Latin loanwords. Maybe students are happy as long as they learn nothing but their native language. But if they go on with French, English and Latin, the disruption will show and it will be more difficult. Bitching about the reform of a spelling you've learned in school is selfish. If you know the history of the German language, and are honest, you will generally question the Duden as it became official spelling around 1900. The stupid student in 1750 spelled "marchieren" instead of "marchiren", because "manieren" was spelled with ie as well. "Manier" is the correct French loanword indeed, but "-iren" is the German form of the old French ending "-ir". The correct spellings were "marchiren" and "manieren". Today this German lection of grammar is dumbed down to "marschieren", so you can't see that the ending once came from France. These things should always remain obvious in any language, because we have to consider the broader sense of European languages all together. What happened instead, was oversimplification. You find these tendencies in pretty much all languages, but the Germans around the year 1900 brought this to the boil of perversion. This had quite some unpleasant consequences.....
Maybe, you've heard, that the German language isn't really ideal for singing. The famous Caruso sang Italian, French, Spanish, English, Russian and probably more languages—but he refused to sing German, because he feared for his voice. Long before Caruso, the German language had had way more variation, and with it many options to involve vowels you could use or drop. You were free so say either "kommt alle" or "kommet all(e)". Or how about this: "Die Bauren tanzeten"—in modern German: "Die Bauern tanzten." Try to sing this modern clustering of consonants: "Die-Baue-rnta-ntzte-n." That's how opera singers manage to sing German. The oppressiveness of consonants is being condensed and articulated as fast as possible, so the few vowels can somewhat ring out. It works, but it will always be unsatisfying, until the Germans go back to their roots of considering more than just one spelling correct.