On my own money, I would fly WN on BUR-SJC. For a regular intra-California commute, I just don't think the hassle of getting to LAX and/or SFO is really worth it. BUR-SFO had a lot of CR2s also, not sure to what degree that will permanently stay away.
BUR is going to be the easier upgrade, but the schedule is poor compared to LAX. Not sure I see that much value in a sub-500 mile CPU.. you'll spend more time getting to/from the airport than on a plane anyway.