I really like UA expanding any service to so cal and think they can and should increase international capacity out of there. They have EWR/IAD which are even closer than SFO/LAX and have even more population to draw from.
I'd like to see Ontario expand as that is a nice alternative domestically as well. You are not fighting traffic if you fly into and out of Ontario. You can get to Orange County and into downtown LA easier than from LAX depending on hours. Put in some Ontario - Hub traffic (ORD/IAH/SFO/DEN, which exists now) and then increase the LAX international traffic by going to Central/South America and Asia/Australia more frequently. You would have to increase frequency to IAD/ORD and ensure PS schedules feed LAX from EWR and even BOS which is in SFO now.