As a Detroit expat and the resident A.net Detroit sports historian, I can tell you that Tiger stadium won't be demolished anytime soon. With the Tigers playing so poorly, the team might need to play a few games in the old park just to generate excitement. Also, Tiger Stadium is on the list of National Historic buildings. It's really a meaningless distinction.
There have been various plans floated to convert the old park into a new urban mall with apartments, etc. There is no need for such a product. Sevenfifty7 is right about the blight in the downtown Detroit area; I have been in both Detroit and Sarajevo in the past year, and the latter is in better shape!
So for now, the old park stays.
Maggs swings, it's a drive deep to left! The Tigers are going to the World Series!!!