As the subject line suggests, this isn't exactly the end of the word, just a very very minor annoyance with Mail 2.0 in Tiger. When I go to my Sent Items folder, previously, a message sent to multiple people would show up in the "To" column as "John Smith, Jane Doe, Jim Se..." Now, in Tiger's Mail, it just lists the first name, so as I look in my Sent Items folder, it appears that I only sent the message to one person. If I'm looking for a message that I sent to multiple people, this makes it harder to find it.
As I said, just a minor issue, but it's one of those things that makes me wonder why they changed it at all. If it ain't broke...
-birdman