Comment by WalterBright

C is a simple language, but that simplicity leads to non-portable code and lots of klunky, ugly things like using the preprocessor as a substitute for conditional compilation, imports, lambdas, metaprogramming, etc.

You don't have to use unneeded features that are in D. The core language is as simple as C, to the point where it is easy to translate C to D (in fact, the compiler will do it for you!).