From my perspective, though, the largest annoyance of PR reviewing is that diffs are alphabetical instead of conceptual.
For example, a large change ends up affecting 26 files named A, B, ... Z. The PR diff/review lists the changes starting with A and the last changes reviewed are in Z. But, conceptually, often it'll be that - if you made the PR - you'd rather the reviewer start with Z: the high level, this is why the PR was even needed, then jump to F: the data structure change enabling this, then off to B: initialization code that needed to account for the structure changes, etc, etc.
Currently, the only way around this - that I know of - is with the comments section and just noting for whoever reviews it what to look at in what order.
Having a tool that fixed that problem would be heaven to me.