The 17 runways have this terrible wind pattern at approach altitude. The grounds can be calm but aloft winds can be blowing 20+. Cross wind landings are fun there. If you can land KAPA then you can do them anywhere.
If you look at the radar track, it looks like the Cirrus and the GA aircraft before him overshot 17R on the base leg and had to correct on final. Unfortunately, the Cirrus’ turn to final put him right on top of the Metro. Don’t know if wind was a factor at pattern altitude, but if the centerlines are only 700’ apart as you said earlier, I would bet it was more a case of sloppy pattern work more than winds aloft.
However, I still can’t understand why the controller didn’t extend the Cirrus’ downwind leg to allow the Metro to land before the Cirrus.
I believe the Cirrus over the fence speed is around 80kts and I am assuming the Metro is significantly higher because of the turboprops. It just doesn’t make sense to sequence a GA and commercial aircraft on a visual approach into the “same” airspace simultaneously. Granted, in the real world this has probably been done without incident before, but on a non-instrument approach it just sounds like asking for trouble.