Detroit is un-fixable. Just let it die already.
Detroit can definately be saved. What they need to is focus on crime and Education. Those two things contribute to the continuing exodus of the middle class white and black. I generally like what Fezzy and Snowyguy have said.
There Education system is a complete joke and all attempts to reform it have been blocked by the school board and the city council. A year or two ago, I recall that a rich businessman offered to spend I think $20 million of his own money and open up charter schools. He was rejected on the grounds that it would undermine the public school system, and they were afraid of what this evil rich white Republican businessman would teach these innocent African Americans(Maybe he would teach them to think for themselves and not be pawns to the big city political machines). What public school system is there to undermine? Charter schools worked in New Orleans and it would force the regular school system to reform.
In terms of crime they need to take a look at what NYC did in the early 90's. They shuld not copy it 100% b/c Detroit isn't NYC but it needs to be looked at cause there situations are similar.
Thirdly Detroit needs to make the city more favorable to small Business. I heard a few years back a proposal where the federal Gov't could create a special classification for certain cites are that really in trouble like Detroit. Where in return for reforms to education and crime fighting the Fed Gov't would lift or lower certain taxes just for those cities to encourage Business and development in those areas. I don't know it it would work but it is definatly something to consider.
I do agree it can't be done all at once and it has to start at the cities center and work outward.