My little story:
Flying RST-MSP-AMS-MUC yesterday. Some fog in RST so all flights were late. Mine would give me less than an hour in MSP and who knows if it could get worse. DL.com tells me I should rebook my flights and gives me the choice to rebook on the earlier RST-MSP flight (nice feature) that is now running late. But I worry about loosing my exit row seat on the MSP-AMS leg so I show up at the airport early thinking I can just rebook on the earlier flight.
At the airport, they can not put me on the earlier flight despite availability. The Delta system does not like the fact that my AMS-MUC is on KLM. The agent did call twice for help but he could not find a way to print a BP. This is something I did all the time on NW! I did make my connection but what a pain that a simple "standby" is so difficult to do.

I do not mind the integration of NW into DL but this is another example where NW flyers are going back in time dealing with antiquated systems.