> In effect, instead of building the core while trying to anticipate what might be needed at the other layers, you just simulate the other layers by actually building them.

Eh. I think you're just going to end up with slop, or sloppy recommendations?

My experience is that you can make different trade-offs for different reasons. I think even asking for the best answer to "improve the code, make better trade-offs".. even if you got a perfect response, there's no reason to think that it's the same set of trade-offs your actual use cases would benefit from.