I wouldn't be too concerned about a 30+ minute connection in MSP. Assuming no weather or mechanical delays (which could happen on any given aircraft at any given airport), you'll likely arrive early. MSP is the #1 most on-time airport (MSP Airport is No. 1 in on-time performance, report finds - StarTribune.com) and Delta overall as the most on-time airline. Your odds are about as good as they could get for a smooth connection at MSP on Delta.