If you are actualy based out of DTW I would recommend writing a clear explanation to NW and asking them to status match you - it does stand a good chance since you have relocated to one of their major hubs (I know there's technically no poaching, but given enough cause, they usually will do it anyways).

You'll only get 50% EQM's on cheap CO fares on WP.. Its bidirectional; but on NW and DL you'll always get 100% EQM's at a minimum - NW is quite generous about mileage promotions (milesafari, elite extra for example this year )