While in general I love the SWA website, I do have a suggestion as well as an observation of a minor issue.
Suggestion: make flight status check an option on mobile.southwest.com
Minor issue: Occasionally when I'm booking new flights, I'll get an error page "your session has timed out, please start over". This is even when I have just clicked on "book trip" and started the purchase process. It happens often enough on multiple PCs that I don't think it's a cookie or local issue, but a web server issue. Would be nice if this happened much less often or not at all.