Amen!!!
Me and my other 3 roomates are in the same kind of situation. We (me and 2 of the roomates) like to keep the apartment at 71-74, but some mornings we would wake up sweating and go to turn the air down and it had been set at 80! We love our fourth roomate but we had to lay down the law. She is always freezing. Now instead of going straight to the thermostat she has learned to layer clothing. Just like you said, if she is cold she can put on more clothes. However, ther's only so much we can take off.
Personally, I can't sleep comfortably when its hot. I Definitly find it hard to fall asleep while sweating

So, you are not alone in the thermostat wars