I think spec review, which is definitely valuable, solves a different problem. One question to ask is "are we building the right thing", which a spec review definitely helps to answer.

But another question is "did we build what we planned, and did we build it to a high quality". Code review partially answered that question. Adversarial review is the closest we have to that in the automated LLM world, but I feel we need something better.

In the sense that ai-engineering specs (ie an elaborate prompt with skills etc.) can be said to be compiled into code language x maybe.....the spec is the new code?