Sounds great, but here is the issue...
If the strikes don't actually hurt, and you can be smashed over the head with a staff repeatedly without effect - then it is not a valid fight.
It becomes D&D Gladiators... You fight each other until you do enough "hit points" of damage to kill.
Instead of being Rolemaster Gladiators... As you fight and are injured, your offense and defense are both weakened - leading to a downward spiral that brings you to your "death"
And if they really want to make it cool and exciting, during the combat there should be included a camouflaged (since invisibility is not possible) turtle walking on the battlefield.