Does this spells the end of leechers?

I didnt forget the Level aspect.

If I am in a party with a lv 190 Bishop (30 lv dif) how will that be any different from a low lv leeching from a high lv? The question remains, how will they differentiate one from the other?

I'm not sure. I think that they should detect the last time you attacked a monster, and if it was more than like 10 seconds you stop receiving exp. You should also have to do do most of the damage to the monster when it's killed for this to take effect. (Eg, you have to be attacking newties and kill one atleast once every 10 seconds to get the experience.)

I think the whole leeching problem is stupid. I think Nexon should just declare paying for leech is illigit, which would stop everyone but the people that want to sell/buy leech so badly they'll take the chance of being banned. It would be nice if the community itself would decide to stop leeching. Hell, the people buying leech with NX is in itself illigit.