Maybe it would be nais, but you have half a billion native speakers to convince, and then about the same amount who are trying to learn it as best they could. ;)

If you're wondering why it all looks so messy, it is a result of history. We've borrowed a lot of words from other languages, as well as some odd rules for grammar, pronunciation and writing. If you look at English as a developing language through history, there are about 1,500 years of changes and influences to think about!

To answer your basic questions, the s/k pronunciation for C is borrowed from French. When it doesn't follow this rule, it might be a Gaelic influence. Or Italian! Who knows? :) The pronunciation of end and and depends on our accent. I pronounce them differently.

There have been a few attempts to make English perfectly phonetic, but none have caught on. See my comment above about the half-billion people you need to convince.

The only time fonetik raiting has caught on is via funny pictures of cats on the internet.

It's just history and tradition, and the last serious attempt to phoneticize English-- the "Shaw alphabet"--was a dismal failure. I expect to see decimal time (ten hours in a day), calendar reform, and a single world currency long before I expect to see English speakers adopt phonetic spelling.

I apologize to all foreign learners on behalf of the English language. I can't explain it. I can't even begin to imagine the trillions of wasted hours of human effort expended by English-speaking schoolchildren on spelling. 

The typewriter keyboard is often used as an example of the way silly and arbitrary things get "locked in." The original QWERTY layout was designed to reduce typewriter typebars from jamming by making sure that frequently used pairs of letters physically well-separated in the type basket. The mechanical problems were specific to early typewriter designs. By the 1920s or so there was no longer any reason for it. Certainly there is no logical reason for it today, and while its advantages can be exaggerated, there is fairly good evidence that the Dvorak keyboard layout is a bit better from the point of view of the typist, and allows faster typing with fewer mistakes.

But the QWERTY keyboard persists and the Dvorak layout has made almost no impact, even though for twenty years or more it has been perfectly easy to select a Dvorak layout on a computer keyboard through software. 

The QWERTY keyboard persists because so many people have learned to touch-type with that layout, and people continue to learn that layout because most keyboards continue to use it.

If we can't break the hold of tradition on something as relatively simple (and relatively new) as keyboard layout, what do you think are the chances of doing it with a whole language?

Other languages also show this phenomenon, not only English. The letter c is pronounced [k] when followed by "a", "o" or "u" in Spanish and Italian, like in "casi", "comer" or "acuto". When followed by "e" or "i" it is pronounced [θ] in Spanish (gracias, cereal) and [tʃ] in Italian (certo, ciao). Also, the pronunciation of the letter g differs, for example gato vs. general in Spanish or gatto vs. gelo in Italian.