the class and job quests in this game

[Ryans]

Because even in the main quests, the echo is anecdotal. :s
Only v1 players know it's supposed to be fundamental.

I wouldn't say the echo was anecdotal in any way. It was definitely a key factor in why your character was successful in the storyline. Being gifted with the echo is what let you resist the primals' influences and, with the aid of Hydalen or whatever her name is, beat Ultima Weapon. Without the echo, or at least being protected by Hydalen, you'd be dead a few times over.