Delta has one of the worst customer support, Alaska - the best. There is absolutely no reason for Alaska Airlines to couple up with an airline like Delta, which merged with Northworst Airlines not too long ago.
This would be good for Delta only, they would get team members focused on customer service. Furthermore, they would get a fleet of fairly new 737's and retire some of the gas guzzling DC-9's from Northwest as well as some of the MD-80's and A-319's and 20's.
Delta and Alaska have a few overlapping routes from Seattle which could be eleiminated. Delta would also gain access to DCA from LAX. I notice the Alaska terminal at LAX is being moved next to the DAL terminal at LAX.