I think what people forget is that the back of the end zone is also out of bounds.I disagree. Players already get let off the hook a LOT for fumbling, either because it happens to bounce right back to a teammate, or it goes out of bounds before the other team can grab it. All they have to do is get the ball one Planck Length over the outer edge of goal line and they're automatically awarded a touchdown. They can hang on to the ball if they don't want to lose possession, and the current rule is in line with every other rule associated with change of possession and touchbacks, such as fumbling back through your own end zone becoming a safety.
So if a defensive player punches the ball out and it goes through the back of then end zone that is also a turnover and touchback. And honestly in that case I would say that IS the "right" result. Why should the offense benefit for fumbling near the goal line instead of at the 50 yard line?
So really you would want to change it to fumble out the side of the end zone = offense gets on the 1 yard, fumble out the back = turnover. But what about if it goes out of bounds through the corner?
I would say keep the rule how it is. It is simpler and consistent in general with how the end zone is treated. The end zone is special, so why shouldn't fumbles through be different?