Of course, if lines on the Southwest side are bad, you can always walk the short distance to the other terminal and go through security there, then connect back airside. Southwest has been operating flights from some of the gates at the end of Terminal 1, in addition to its Terminal 2 flights. If your flight is leaving from T1, it might even be more convenient to go through T1 security--although they're so close, it's not a big deal either way.

-Hayden