I understand your point completely.  The counterpoint I made above is that using your argument, I can make an equally valid one for a different cast order, based on the order in which they appear on the official Grey's Anatomy page.  Personally, I think the most accurate way of listing them is as billed, in the opening credits.  Yes, they do say "with-and".  They could say "featuring-and" or simply "and".  Ultimately, IW and PD are billed last in the credits, so they should be listed last here if the general consensus is to use billing order for listing the cast.  That's the great thing about these discussion pagesit allows for differences of opinion to be expressed and consensus reached.  Currently, there are three opinions on record; two of them support listing the cast, as billed in opening credits, regardless of the "with-and" structure.  Hopefully others will chime in with their thoughts or opinions.  I apologize if you felt I was undermining your argument.