The bottom line to Nepenthe was that he was going to play the game all out.
He was going to spend weeks writing the "perfect role." He was going to RP his tail off.
He was going to use every bit of area/game/quest knowledge at his disposal to PK.
He was going to use all of his knowledge to explore areas that no one had explored before and start cycling gear no one had ever seen before, and show people how to use the gear no one knew how to use before.
MAYBE he'd hold back a little sometimes .. I think he said he got bored winning all the time .. but there is not a lot of separation between him holding back and not, because his knowledge about the game was so vast.
That's the kind of character that is going to get rewarded by other IMMs.
In fact, the only way Nepenthe could have avoided special skills from other IMMs is to make his first role entry "I am Nepenthe. Please don't reward this character, ever." But that would probably have the opposite effect, since most IMMs would spend an even more inordinate amount of time snooping the character, or worse, try to talk about the character with him.
I'll agree Nepenthe characters were "unfair" and were not playing on the same level playing field as all the rest of us. But IMO that's not the same thing as cheating.