At high levels, a simple Bandit marauder with orc or elven arrows can do one hit kills. The bandits (and other foes as well) are able to do damage that seems to defy the formulas used to calculate the damage done by players. ...level scaling...

They learned to make enemies dangerous, in Morrowind nothing was able to kill you at level 25 and you killed everything in a couple of hits.
They changed this in Oblivion enemies was a bit more dangerous but as you and enemies got load of health at high level making fights long, drawn out but not dangerous as the enemies did to little damage.
Fallout 3, a bit better but still just the rocked launcher and exploding cars was really dangerous.
Broken steel and they broke the enemy do as much damage as you would do with their gear rule. Worked well as it was brutal hard.
If the bandits running around in fur armor had followed the same rule as the player they had been killed off by the mudcrabs.