I know this will never happen but I can dream!
When you get a jutsu to 100% in this case we will refer to rasengan.
Once this skill is raised to its max you will be given the option to upgrade. This upgrade will increase the jutsu's damage but in turn send it back down to 50%.
Rasengan 1 = 10-20 damage
Rasengan 2 = 20-40 damage
Rasengan 3 = 40-50 damage
Rasengan 4 = 50-60 damage
Rasengan 5 = 100-200 damage
Gaining level 5 for a jutsu would be difficult and only can be done with 1 jutsu. This jutsu in turn would be your signature jutsu the skill you are known for.
It goes without saying that the damage is obviously just an example.
