Ah, the perennial post about poor, useless Minfilia.
Louisoix was a boss, sorta true, but he had few organizing skills. He certainly didn't set up the Path of the Twelve or teach those who joined how to use the Echo to bring about peace. He was the leader of the Circle of Knowing, which included all of the Archons you've come to know and love, but I don't believe he had any of the skills necessary to actually run a group like the Path of the Twelve (or, later the Scions of the Seventh Dawn). The Circle of Knowing always struck me as more a 'hands on' group than administrators.
So, anyway, without Minfilia there would be no Scions, and you, as an adventurer, would keep blacking out and wondering just how sane you were without her assurance that it was a gift, and not a curse. Unlike the Circle, most of those associated with the Scions do not have the Echo. Without her, all of those great contacts with the high muckety mucks in-game (you know who they are) would have been one-shots.
By the way, the Scions are not 'dedicated' to the Primal threat, although that is high up on their list. There are plenty of non-Echo members doing things you never know about, all under the auspices of Minfilia's leadership. Generals (with a few exceptions in Ul'dah) do not usually stand at the front of the army, why would you expect her to do so? Leaders don't have to be able to beat up a Primal -- that's your job.
(If you want to learn about the non-Archon members of the Scions, go to the room off of the Solar where they congregate and talk to them ... each and every time you come back you'll learn a bit more about the depth and breadth of this organization).