I know that the tower at the Westland Police Station is the Main Tower, so that one is not going to go anywhere, nor has there been any talks about it.
There was talk about putting a 300' tower behind dearborn Heights Police Station, but a lot of people have pitched a fit over it, so last I heard it was still in the holding stages. When and if they put a tower at DHPD station, it will be an additional tower to provide coverage, no towers will be taken out of service.
Hope that helps
Eric