People always get advantages by having connection to the more powerful, richer people. It is always the case, it will never change. Maybe the developers can put some detection to limit this (in case of a party with members having too far levels then monsters won’t take damage from the lower level players if the monsters are targeting the higher level ones, etc). Letting people leeching each other to some extend wouldn’t hurt as much as punishing all players for wanting to use their skills and seek challenge.
Now it’s kind of ridiculous for them wanting to prevent leeching doing things like all the while letting the EXP shared while players ain’t even on a same map (one in town, the other are in a dungeon fighting, yet the EXP is still shared between the two).