And I think of idea of complete extraction of GC from D.
You could also recompile the runtime library without the GC. Heck, with the new @nogc on your main, the compiler (rather than the linker) should even give you nicish error messages if you try to use it, but I've done it before that was an option.
Generally though, GC fear is overblown. Use it in most places and just don't use it where it makes things worse.
