^ Fascinating. For a building to go from a department store, to a city hall, to a mixed-use development is a pretty unique sequence. Here's the
street view - the building as-is appears to have very little worth preserving. So I guess the massive overhaul implied by the rendering is OK. I'm not crazy about the aesthetics of the proposed redevelopment, but a 3-story vertical addition is pretty interesting, and they are recalling some of the look of the original architecture.
When it was a Federal Department Store, 1940's -

Source:
flickr | Downriver History & Facts
When it was City Hall (I'm guessing late 1960's or early 1970's) -

Source:
flickr | Downriver History & Facts