From my humble opinion. The best thing for KLM would be the death of NWA. KLM, is day in and day out relying more and more on that of Air France. Air France, has made it well known that things are going to be changing more and more with their business model as the years go on.
A few things to look for if NWA ends service - Memphis, Minneapolis, Detroit, Seattle would loose service to Amsterdam. Boston would regain service ala KLM. Vancouver would see an increase in service at the expense of Seattle. Los Angeles would more than likely regain its summer seasonal second flight.
KLM, would reduce the number of connecting flights within Europe. KLM, would take over all Amsterdam-India flights now flown by NWA. There in most cases would be a stronger link made between KLM and DL
/CO, at the expense of what was lost with NW
. KLM, would more than likely increase aircraft size to EWR
via the 772.
There is nothing lost with the end of NWA. Continental and Delta, could make up for NWA in a heartbeat.