I think the solution is that the airline should weigh all of your luggage, carry-on and checked at the time of your check in and you should pay per pound.
I think the passengers should get up on the scale too. It is total BS someone like me who is a tall athletic male should be crammed into some BS coach seat and nickel and dimed for each of my small bags and some fat @$$ strolls on board with a steamer trunk and doesn't pay a penny more.
You are tall - you take space. They should also measure you. This short fat sh**t thinks nobody above 6´ should be allowed on a plane - they are clearly oversized. Tall and athletic guys should simply run wherever they need to get to.