With a trait-first implementation that mostly defers monomorphization and prefers "static if" over C++-style specialized implementations, the only hard choice is whether to optimize codegen for size or speed.

Trying to retrofit this onto standard C++ is ... not actually as difficult as you might think. The real problem is the implementation of builtins that rely heavily on "this really must be a constant during X phase of compilation".

‘requiring generics’ -> C++ Templates -> massive ASTs

Is that correct? If so I’d then wonder if the applies from strictly within the bounds of C++ the language. Is there an alternate meaning? I think there are quite a few viable ways to present what are usually called ‘generics’ at several levels of abstraction and in several programming paradigms, so any reading outside of C++ seems strange.