Messages got three new features worth mentioning. You can now edit messages, undo send, and mark them as unread. Of the three, editing is likely the one most people will get excited about, but honestly, I think the latter is the most interesting.
I’m not sure using your message inbox as a todo list is the best productivity tip, but the truth is, there are plenty of times you read a message and think “I need to respond to that later,” only to forget.
As for the ability to edit messages, the only question I have is, if Apple can do it, what is Twitter waiting for?