Detroit actually has three terminals.
A and C are connected by a long underground tunnel. A itself is quite a long terminal and has an overhead tram that runs end to end with only (I think) one stop in the middle.
The North terminal opened last September and most of the low-cost airlines fly out of there (Spirit, Airtran, SW, etc).
Soooo .... if your flight arrives on time and your next flight is a bit delayed, you will probably make it. If you think you will be arriving and departing from gates at the same terminal and they are near each other, you will probably make it.
If you are coming/going just within the North terminal, I think you would be okay.
Iffy, iffy ... if you like to live on the edge, go for it.