Just a technical comment on the logistics of implementing this if it was added.
As was slightly touched on in the latest server update announcement as to why the alternate DNS option cannot be removed from the log in screen. It isn't really possible to make any updates to the Nightmist Client at the moment.
As I posted at the time:
"Updating the client log in window will present further issues for users of WinVista, Win7, Win8", which is presumably most users currently.