I think this skill is being appropriately rewarded with the rule as it is, and if I had to move it one way or the other, would give the offense better position, not worse (maybe put it on the goal line in the center).
Pulling a good roller is (usually) a skill, but not one that is really core to the game. A good floaty pull has many similarities to a good huck. A roller is unlike any other ultimate throw. Therefore, a reward of having the offense start from a stagnant situation (and on the sideline if out of bounds) is sufficient and doesn’t need an additional reward of yardage.
Also, the roller is frequently used on downwind pulls when it is already hard enough for the offense to score. If they also had to start at the back of the endzone, it would be almost impossible to score. Upwind rollers generally roll out short of the endzone so wouldn’t be affected by this proposed change.