> in an ideal world, most of the questions you're asking here should be addressed before anyone writes code.
I agree completely. But code review to me is the chance to pick up on those situations where the situation wasn’t ideal. And even if this is just one time of 100, that review was still more important than the remaining 100 “normal” reviews with more mundane feedback.
A basic spec, with "here's the idea", "here's how I plan to prove the concept viable", and a rough plan of "here are the software components I'll use" doesn't take long to put together, relative to actually coding the thing up.
Having that document and getting it reviewed should answer a lot of those questions before code is committed to paper.