My advice on implementing stuff in C:

OK, so C was invented in 1972, ML was invented in 1973. ML had a revolutionary type system (including polymorphism, type inference and algebraic data types), it had a powerful module system, and it didn't have a preprocessor because it didn't need one.
At least some of these innovations could have been copied by C without compromising the suitability for systems programming, for example the idea of strong typing and the module system; they just didn't do it.

Also, even if they hadn't known about the necessity of modules, generic algorithms and data structures etc., they could have added them later on when it became apparent; for example Ada had generic programming features in '83.