Earlier quoted context omitted.
> Mondrian had some definite deficiencies You mean like its approximately two 8s uptime? :P I do think you're spot on about how Mondrian encourages the nit-picking and doesn't do enough to encourage structural discussions. On the other hand, maybe those discussions should be had before there's any code to review. So . . . meh. Tough problem.
I've always found it hard to do something like a structural discussion without having written some code first. At Google I found that I could request an informal code review in email rather than using the formal request mechanism ("g4 mail"). I could even provide a changelist number so the reviewer could look at it in Mondrian. But by having used email I could frame things so the reviewer would look at the high-level…
Another nice feature of that is that if parts of the design discussion pertain to particular features in the code, you can attach them as such, so that the code is automatically quoted in the e-mail thread.