For security purposes alone, people need to be able to see the senders email address at a glance or by clicking on the user name at the very least. The latest version of mail is great in many ways and the progress is good, but the fact remains that e-mail is a cesspit of phishing and malware and always will be.
Making it necessary to drill down to the command to view the entire message source just to see the sender’s email address is not optimal, to say the least.
You can also click the sender and copy the mail address to the clipboard, open another window of some kind and paste it in and then read it, but that’s extremely sub-optimal as well.
If I could see that I was mailed from noreply @ em4750.mailer.maidily.com I’d know right away it was total bullshit. But all I see as sender in the mail app is a name, that looks perfectly innocuous.
So, please stop obfuscating the sender information - ideally I’d like to see the email address at all times in every view - and never take away the ability to see the entire email source as-is. It’s necessary.