We love the fact that directly from Outlook, a user can update an existing Workfront object and a copy of the email can be attached as a document to the object. The attachment is always needed since the update field does not usually allow the entire length of the email due to character limits.
By default, the attached file is always called "email.eml" and cannot be overwritten by the user without them taking the time to manually navigate to the documents folder and renaming the attachment through the interface.(We now have hundreds of documents called "email.eml" and many projects contain multiple files of the same name, making it impossible to find the attachment you are looking for.)
This takes a lot of time and somewhat defeats the purpose of updating directly from Outlook.
I recommend the default title of the email attachment should match the subject line of the email. For bonus points, give the user the ability to rename the title in Outlook before they click the Update button.