I used to get responses nearly every AS Listens survey where something wasn't great. I frequently got $25 - $75 discounts as service gestures. Max up to $150 when things went particularly haywire. I've not gotten a response or any sort of service gesture in the past 3-4 months no matter what happens on my flight (not expecting them necessarily, but they do seem to set some expectations in sending for fairly minor issues).

In addition, they made some changes about 6-8 weeks back that seems to have broken the ability to look-up your reservation by confirmation number and linking flights, so you now have to enter more details and complete a survey for each independent leg of an itinerary.