If you aim to be both a C alternative and C++ alternative, in reality you are just a C++ alternative because you haven't understood why people prefer C over C++. Therefore D is a C++ alternative and that's what it was always trying to be, even with "BetterC".
Most C programmers I know pretty much do that. I use C11 just for the atomics and that is it. And I know many C programmers who still use C89/C90 exclusively.
Well yeah, I use C99. I would never use newer C, it is too C++-esque. You can actually use some stuff from stdatomic.h with -std=c99 -D_XOPEN_SOURCE=700, such as "atomic_bool" and whatnot.