I'm not sure if this is technically possible except for bounced emails. But due to the possibility of merging records that have different email address, email history, and the ability to send emails to a specific email type versus the primary email, it would be helpful if the email address that an email was sent to was included on the history tile. If a record has multiple email addresses on it, and reviewing the email history shows that there was once significant engagement that suddenly dropped off, it would be helpful for the data maintenance staff to see if there was a change in which email address was being used.