When every other Dragoon I see is named Highwind, and an unusually large number of players I've met have never played an MMO before by their own admittance...I do not think it is wrong to assume a lot of people are trying this game because they are Final Fantasy fans.
The PS3 versions especially are enabling people who don't have gaming PCs to play. I've seen a similar thing occur in Phantasy Star Online.
As for the "lore" about the shield, it is a brand new lore made for this game. You're misunderstanding my point there in that we have no emotional attachment to The Twelve because they don't even appear in the game, unless you consider the opening cutscene having a bunch of floating orbs to be an "appearance".
Compared to, say, Odin who has been in like 30 games in the series.