I think I know exactly where they are buildig the new stadium, which will also be accompanied by a retail development, and possibly some residential development (either directly or indirectly). The area in question would add on to the already very successful and growing district which includes Greektown, a couple casinos, Comerica Park and Ford Field, the Fox Theater, some great restraurants, etc...In addition, other old buildings are being bought up and rennovated in the area by sick businessmen (such as the QuickenLoans founder, Dan Gilbert, and others). This core entertainment center is safe -- the streets are crowded when there is a ball game, and the restaurants are packed.
This additional economic center will will pretty much connect this previously mentioned business/entertainment hub to "midtown", which include the Detroit Institute of Artys (a great museum), the D. Science Center, African American History Museum and some other museums, as well as Wayne State University, where a lot of younger peole obviously dwell.
It creates a larger zone of economic activity and safety...which means the "fringes" of these areas start to grow, blossom, etc....this is how a city grows and revitalizes.
The funding does not, in any way, tax tax revenue from the city itself.
This has nothing to do with the backrupcy. Bankruptcy is a city budget issue, which has nothing to do with economic development (or only peripherally does).
The stadium will be a great thing for the city, and another positive step that the city is on the come-back.