Is it doable? Yes, but it's a pretty big risk with 15-minute cutoff. I had a connection from the end of concourse A to the end of concourse E at ATL with 15 minutes to go until scheduled departure. I ran pretty hard, took the trains, didn't stop for a bathroom break, and it took me 14 minutes to get there. Of course, they had already closed the flight out by the time I got there. Bottomline, worst case connection at ATL is worse than either DTW or MSP even if you know what you are doing.
If it were a "pretty big risk" then delta would be rebooking literally millions of people who book these tickets each year, and hemorrhaging money in the process.
Is it a risk, yes, of course it is.
Did you misconnect on an apparently late inbound? OK, that's interesting, it happens.
Is a 30 minute connection doable? Yes, absolutely.