SWA was going to Chicago Midway, where the longest runway is 6,500 feet long. Oakland has a 10,520 runway.
if you had gear problems, which would you prefer? (SWA had an overrun accident at MDW once - killed a child off airport on a street).
https://en.wikipedia.org/wiki/Southw...ht_1248_-1.jpg
Pax reported "sparks" during gear retraction, so the exact extent of the problem/damage was unclear. A gear-bay fire might have developed.
Is the gear hanging out and adding drag? You may not be able to make Chicago with the fuel on board.
The first 1000 miles east of OAK are mostly mountains (Sierras and Rockies reach 14,000 feet), desert, and wheat/cornfields, without a lot of places to put down a 737 quickly if something worse developed.
Seems to me (absent more details) it was smart to hang around the big airport, burn off fuel weight if possible, with the option to make a overweight landing on a long runway (with a RON maintenance base) if things rapidly decayed.