Newsletter confirmation emails shouldn't use do-not-reply@yourdomain.org

When sending out automated messages, sometimes CiviMail uses a hardcoded email address as the sender, instead of the email address specified in Mailings => From Email Addresses. The hardcoded email address is do-not-reply@$emailDomain

I find this undesirable for two reasons:
1) The user should be able to choose the sending address from the admin panel, without needing to modify any php files.
2) do-not-reply@$emailDomain implies that the organization doesn't want the receivers to reply. But the organization may want them to reply. In fact, this very common practice of sending from a do-not-reply email addresses leads to poorer IP and domain ratings for the senders. This is because if the receivers reply to your emails, that increases your reputation with the particular mailbox provider (gmail, yahoo, etc.).

Patch submitted here: https://github.com/civicrm/civicrm-core/pull/7498

Also in the patch is contained an adjusted address for the Return-Path: header. The address in that header is where the mail server will return the message if delivery fails. But for some reason, my fix didn't totally work for the Confirm.php file. The value in the Return-Path: header was the same as $domainEmailAddress rather than $bounce_address. I'm guessing the header was somehow not set properly in the send process.

Update:

Submitted two new pull requests for this:
https://github.com/civicrm/civicrm-core/pull/10648
https://github.com/civicrm/civicrm-core/pull/10647

The proposed changes to email headers are:

For the Confirm Your Subscription email:

ReturnPath: - the bounce address which is already used for getting bounced messages from sent Mailings

For the Welcoming email:

From: - the default email address for the organization
ReplyTo: - the default email address for the organization
ReturnPath: - the bounce address which is already used for getting bounced messages from sent Mailings