In real life I don't send e-mails to people I delegate tasks to. There are also times when you are not in the position to do so (for instance, when waiting for feedback from your manager after he reviews a document).
It would be good to be able to just write the name of the person the task is delegated to when moving it to the "Waiting" list, without the need to add an e-mail to contacts.
On the list, I would like to see the name of the person written next to the task, so it's easy to see what is delegated to whom.