Replacing the Michigan Ave lift bridge, which once connected to the outer harbor, seems like a simple way to circumvent the Skyway. But ADM doesn't want a bridge in that spot, because it might interfere with their grain ships. They can be accomodated somehow, I am sure.
Taking down the Skyway isn't the big deal some people might think; when big highways disappear, drivers tend to find several different routes instead. A new bridge needs to be built to what was once called The Hamburg Turnpike, of course. (Big trolley cars once ran alongside it to Lackawanna, Blasdell, and Erie PA - didja know that? )