At the old Robert Mueller airport in Austin, Southwest had 4 gates and operated 44 departures a day or 11 per gate. When the new airport opened, Southwest leased 6 gates and has added 4 new departures for a total of 48 or 8 per gate on average. (Gate 9 in AUS is the experimental dual jetway gate where passengers can board through both the front and the rear of the aircraft, and that gate handles 13 daily departures.) I know in DAL, Southwest has 14 gates and 139 daily departures or about 10 per gate.
But 3 gates for 13 departures? that's not even 5 per gate. It makes me wonder if that's an indication that Southwest will be adding additional flights in the very near future, or if it was more of a case of "We'd better get an extra gate while we can and hopefully these 3 will be adequate for the next 5 or 6 years."