This could easily be done by adding tabs to the form.

Move some of the more arcane settings on the vacation
page to an "advanced" area not normally seen by most users; access to
these features should be controllable by the administrator.  Ideally the
site administrator could decide which options qualify as advanced, but
if a single set needs to be picked they would be:
  -My email addresses
  -Addresses not to send replies to
  -Do not send replies to bulk or list messages
  -Number of days between vacation replies

Basic options would be:
  -Subject of vacation message
  -Reason (perhaps better labeled "Text of vacation message")

This would dovetail with a separate enhancement request I am 
submitting, an hook that could be used to automatically populate "my 
email addresses" from a directory.