- Formatting is useful, and should be used as needed, especially headings and, as indicated, color. Don't become a plaintext zealot. It's not a good hill to die on.
- Emails, like all communication, should be as short as possible -- but no shorter. Brevity itself is not a useful thing.
- The 2nd bullet is, about the request as a distinct paragraph, is good. A proper email that requests action should make that requested action VERY clear, along with expectations and ideally a timeline.
- Contrary to this assertion, email is actually an EXCELLENT forum for discussion in the right context. This is because email is easy to archive, and leaves a trail of the discussion. It's not the ONLY venue, but it's very useful, and in my career has been commonly used as such.