Code review that isn't boring

If scenario 2 or 3 is a regular occurrence then 1 of 2 things is true - your team is too large for the code base (so people are crawling over each other), or the underlying code is too coupled together (so people are stepping on each others toes) - either way the team is going to spend too much time merging in each others changes - compared to say writing actual code.

Reviewboard has had the ability to compare different versions of the diff for a long time. I don't see anything new or innovative being proposed in this post.

I have yet to come across a review tool which provides inline code coverage (with before and after snapshots) - this would allow me to check that a) any tests included actually exercise the new code b) the new code hasn't impacted the testability of old code. - It isn't a guarantee but it would be an easier way to do the job.