Now that Messages can be sent to a phone number and email for specific contacts, I think the Messages should show the email/phone number under the contact's name to indicate which message thread you're replying to. Sometimes it is confusing to get a message from a person's phone number then you get a separate message thread from their email but its two different conversations and I end up replying to their email going to their laptop instead of the phone.
Attached is a little mockup of what I am trying to convey.
Attached is a little mockup of what I am trying to convey.