The pronunciation of C in Spanish is context dependent. Before I or E, it shares the same sound as S. Before A, O, or U, the same sound as QU.

Or how about G? It makes one sound before I or E, another before A, O, UE, or UI, and yet another before UA.

Lots of folks think their language is simpler, but it's only because they can follow the rules so well they don't need to actually know them.

"Context dependent" here means a different thing than it means in English, where the pronunciation of letters depends on the word they're in, without any hard rule. To the point of being pronounced in different ways even in homonyms: e.g. "tear" noun and "tear" verb.

The fact that there are a few rules on how to pronounce combinations of letters (and even a few exceptions here and there) has nothing to do with the total mess that is English.

I think the point is that you can derive the pronunciation from the spelling (though not, arguably, the other way round).

Would it be sane to have a special letter to distinguish the "p" in "park" from the "p" in "spark"? In some languages, it's important, but these two sounds can be represented by the same letter in others because they don't "compete" for the same contexts.

(the difference is aspirate vs. non-aspirate)