I disagree.

I can't be certain from reading the release, but QPX may not even be running SWA searches yet. (Luckily ITA does a better job writing software than they did with this press release.) It appears QPX will at some point replace SWA's current (or recently retired?) fare search engine. (The fare search engine runs behind the scenes after you feed it your search request.) The slowness issues I documented above are all related to the front end. As noted in the press release, QPX is already used by SideStep, Hotwire, other airlines, etc. If QPX were the source of the slowness, we wouldn't see such a dramatic performance difference between the SideStep UI and the SWA UI.

I infer from the press release that SWA has decided it is cheaper for them to license third party software than it is to rewrite their own fare search engine in hopes of catching up to (constantly evolving) industry standards. Someday we'll see which QPX features SWA chooses to offer via southwest.com. Alternate airports, flexible dates, weekend searches, and more complete/accurate fare calendar searches are several possibilities. To explore the features offered by QPX, log in as guest at ITA's demo page.

I don't know whether SWA will be able to (or want to) connect the system used by RSAs to the QPX search engine.