I'm surprised STL is so down on the list. But let's get real, WN sells some pretty off the wall connections via random 'focus cities'.
Ex: a last minute SDF to LAS offered a BWI connect option. Another fun one was SDF to STL via MCO. I guess if they offer it people must be buying it.
Last minute stuff can lead to some pretty weird routings, especially if it's IROPS. When I was a WN CSA in DEN, I had people misconnect heading to IND on the last nonstop of the day. The option I resorted to for them since a STL or MDW option weren't viable was to send them to MCO for an overnight then off to IND first thing in the morning. MCO-IND was actually the first WN arrival into IND for that day around 0700 I believe. They were very cool about the offering and took me up on it.
Some not so cool customers I had for a last minute connection were some people coming from STL to get to SEA. My sup told my ops agent to pull the jetbridges and close the flight while these people were at the gate fighting with me and my sup. Fighting with me so much that they were almost yelling at me to find another seat and I told them there weren't any because the flight had closed and was as good as gone. Somehow there was an extra LAS segment that night and I managed to get the group of 9 on the flight to LAS then I had to split to a group of 4 and another of 5 to SEA. One group went nonstop and the other went via SMF. Low and behold, a couple hours later the FO of the LAS flight called fatigue and me and other CSAs had to deal with reaccomodating that flight and guess which group of people came up to me... They were insinuating it was my fault and blah blah blah and wanted compensation for a wx delay (inbound came in late) and that they were going to fly another airline blah blah blah. Upon the second try of rebooking, I found the only viable way was to send them on DEN-BWI-SEA. They were totally not happy with that. I believe they ended up flying DL via blah
Last outstanding last minute work around was when DEN had a nasty windstorm which messed everything up. A customer came up to me at the counter trying to get to LAX. His first flight cancelled and everything was oversold. I offered DEN-BNA-LAX which he gladly took and he totally understood because turns out he was a former airline employee for Arik Air.
Another stand out is when I had a girl totally flip and start crying when I offered DEN-PHX-EWR with an overnight in PHX when DEN-LGA cancelled. She waivered so long over the last remaining seat until she for some reason had to consult her parents. I had her go to the side since I had a while planes worth of pax to work with. I offered the guy after her the same thing and he gladly took that last seat.
Moral of the story is, when you have a paid ticket, the staff will bend over backwards for you provided you do your part and don't act outrageous. Be happy you're still getting there.