My wife is currently a GM at DL and we are NYC based. She just accepted a position with a company that has their headquarters in SAN and also has factories in DPS (Bali). She also flies JFK/EWR-LAX several times a year to visit her family.

DL is fine for the JFK-LAX route, especially since they are returning an F cabin to that route. DL does not offer non-stop service from NYC-SAN. She can fly on CO EWR-SAN and receive her Skymiles, but the less expensive fare classes on CO only give 50% credit for DL elite miles. As for DPS, she can travel JFK-ICN-DPS on KL and earn Skymiles, as KL is a Skyteam partner and receive a full MQM for the least expensive fare classes.

As we are entering a new year, this is an excellent time to consider other alliances. Should she stick with Skymiles and Skyteam or consider another carrier that is affiliated with a different alliance?

I know I personally would prefer to get to DPS on Cathay or Singapore, which makes both oneworld and Star good options. However I know they can both tend to be restrictive as far as mileage on discounted fares. If Korean (KE I believe, not KL) gives full miles then they may be the best option after all. As far as SAN-JFK, AA serves this route nonstop, and gives full mileage on deep discount fares. Not sure about Star options on this route.

If she's flying a higher fare class, then Asia Miles or AAdvantage would be my choice. But half the choice for me is based on redemption opportunities.

What about switching to CO? They serve LAX and SAN non-stop from NYC and they serve DPS via GUM. I find CO's F product to be miles ahead of DL's and their BF product is superb. Best thing is you can still earn miles if you fly KE NYC-ICN-DPS. EWR-HNL/HKG/NRT-GUM-DPS would probably be a nice routing, but requires two connections instead of one. Other than that AA might be a good choice, but having just switched from DL I am thus far less than impressed, we'll see what happens.