Cabin too warm to sleep
I also hate too-warm cabins (AA is really bad about it, they hand out 90% polyester PJs and thermal blankets, and keep the cabin in the high 70s.) Did you try asking a FA or purser if they would make the cabin cooler to help people sleep?
(On a recent CX flight in F I resorted to sleeping shirtless. I figured my suite was large enough to not be a distraction.)