Mentioned in the "What" section is the matching of the stated goal of the PR with the reality: so rare to find anyone who puts any effort into writing good PR messages (not to mention good commit messages, but that's for another time). Linking to tickets, explaining the rationale, most other context is just skipped because being assumed (or assumed to be communicated through some other channels). Less than ideal.
In general the "what you put in is what you get out" applies very well both for writing good changes and PRs as well as good reviews. Applying similar principles as the author listed, I have a lot of good feedback from people that the comments in reviews helped them improve and occasions for rare actionable feedback on technical know-how.