This right here is probably the most compelling argument against account-wide rep IMO. Can you imagine feeling obligated to roll multiple characters, max level them, and get them running current content to feel like you even have a hope of catching up to others that are already way ahead in rep even though you are doing everything “right” just because they have more chars to leverage?
Imagine how much further ahead people with multiple max-level chars could get just by virtue of having said characters to run the content with, even and especially since the amount of rep-gaining quests are finite?
Imagine being able to unlock actual useful items (not cosmetics) such as the Crafter’s Mark of the First Ones and Memory of Unity in less than a week by virtue of this rep-sharing system?
How is that fair to people that can only play one character?
Yes, rep sharing is convenient and occasionally I wish for it too, but overall the damage it can do is worse than the payoff.