Bismarck.Josiahfk said:
»Terrible Leader
There are two problems with that theory. One: Artorias is touched by the abyss, yes, but it's implied that that makes him physically STRONGER, not weaker. It greatly affected his tactical capacity, sure, but he's probably better off in combat due to the abyss.
Second, technically speaking, in present day, Ornstein is the only surviving member of the group and thus is not technically a leader of anything. He's just too noble to forsake his duty as a guardian of Anor Londo.