Yeah, but they're trying to replace it with more botch. "If constexpr can be used to precompute statically-determinable logic, except except except..."
Constexpr can replace most per-processor macros in a subset of C++. This is a huge improvement over preprocessor macros and functions which are very difficult to refactor. Even if it turns out to be 'botch', we can reason about the 'botch' and find ways to mitigate problems with it through static analysis.