I also found it really really hot on my last flight, I thought it was an anomaly but if it's a general problem that's disturbing.

It was on a 777 YVR-LHR. I specifically chose that flight figuring 9hr would make it easier to sleep. instead I was kept up all night tossing and turning and sweating.

Turning up the heat doesn't make people sleep better. People always complain the summer that they can't sleep due to the heat. Turning *down* the heat and curling up with a blanket makes people sleep.