I just recently arrived into MSP from NRT. My impression was that Delta isn't really considering this a hub. Maybe more an overflow hub for DTW? The immigration/customs area is rather small and it looks like most domestic flights are CRJs . It feels a bit like Memphis, which I guess is the overflow for ATL.

With less and less airlines, there will be a trend to fewer larger hubs. In particular Delta has some savings potential which I think they in part didn't realize yet because they have to honor some of the pre-merger contracts.

CVG, MEM, MSP are certainly "weak" right now. I would bet that Delta would rather shift resources further west (SEA?, which more SEA-Asia flight?)