I think that's more a libraries thing that a language thing. For example, you can do very cool, HTMLy things using Racket's web-server/servlet and Scheme continuations, which would be incredibly hard to do in C.

But I agree with your suggestion that C should be teached first. If anything, because C's "computational model" is very simple: you know what executes when; it encourages a more common, procedural way of thinking, and it's easy to do side effects in single-threaded C.