To start with the suggestion threads, here's mine:

About the date selector combo that appears on top of the messages pane whenever you have unread threads from several days: I would suggest the date selector combo appear in both the top and the bottom of the messages pane. It only makes sense, since once you're done scrolling down the message pane you're at the bottom. As you are aware, at this time you have to scroll all the way up to select a different date.

Your comments are appreciated, yea or nay.