(Not OP) Usually when I am using this technique it's for some 3rd party library that provides a useful debugging tool. To use your suggestions I'd need to create a wrapper that calls through to the 3rd party library in dev. Sounds like a huge pain.
You should be able to use Loader config for some of this: With the right plugin to your Loader you could do things similar to AOP/injection in debug/dev with a suitably complex Loader or set of Loader plugins.
Arguably things like this are part of why standardizing the Loader APIs has been so complex. But eventually it may pay out by letting you do some nice things very simply and in a way that is configurable for different environments and also transparent from your configuration how complicated or not your libraries and plugins may be set up. (Whereas dynamic rewriting in memory and dynamic loading and lots of scattered if() blocks can feel much more opaque.)
