Well this sounds very messy, the fact you can't change the stack of the thread is a no go for many purposes, just an example, in Redis this must be done because otherwise lzw encryption will cause a stack overflow.

Also the ISO C guys completely miss how important is to provide a better libc with data structures and so forth, very very very well designed.

About the epic quote of C being a language without ambitions, one of the reasons if D or Go, or other languages are going to hardly replace C is that they are indeed, too ambitious. No one is trying to fixing C with minimal but important changes.