A discussion ahead of the implementation can also bias the two parties to that discussion and have them overlook the same implementation issue: many things you only understand once you start implementing.

If you have these parties review each other's code, I agree that rarely brings much value.

I think the best way to understand our experience with reviews is to stop and say: in a few sentences, what do you expect out of a quality code review? (sounds like nothing in your case, but I am curious)